CoderPad

Python Read File

noreply@blogger.com (Nick) — Fri, 27 Jan 2023 15:13:00 +0000

How to Read files in Python?

To read a file in Python, you can use the built-in open() function to open the file, and then use the .read() method to read its contents.

For example:


# Open the file
f = open("example.txt", "r")

# Read the contents of the file
contents = f.read()

# Print the contents
print(contents)

# Close the file
f.close()

You can also use a with statement to automatically close the file after you are done reading it:


with open("example.txt", "r") as f:
    contents = f.read()
    print(contents)

Or you can use for loop to read file line by line:


with open("example.txt", "r") as f:
    for line in f:
        print(line)

python read file line by line

You can for for loop to read file line by line


with open("example.txt", "r") as f:
    for line in f:
        print(line)

Python read file line by line into list

You can use a for loop to read a file line by line, and then use the .append() method to add each line to a list. Here's an example:


# Initialize an empty list
lines = []

# Open the file
with open("example.txt", "r") as f:
    # Loop through each line in the file
    for line in f:
        # Strip the newline character from the end of the line
        line = line.strip()
        # Append the line to the list
        lines.append(line)

# Print the list of lines
print(lines)

Python read file line by line into list

You can also use .readlines() method, it will read all lines and returns a list of lines.


with open("example.txt", "r") as f:
    lines = f.readlines()
    print(lines)

Both of the above examples will open the file "example.txt", read its contents line by line, and store each line in a list called lines. You can then access the lines in the list by their index, like lines[0], lines[1], etc.

Python read file line by line and write to another file

You can use a for loop to read a file line by line, and then use the .write() method to write each line to a new file. Here's an example:


# Open the input file
with open("input.txt", "r") as infile:
    # Open the output file
    with open("output.txt", "w") as outfile:
        # Loop through each line in the input file
        for line in infile:
            # Write the line to the output file
            outfile.write(line)

You can use a for loop to read a file line by line, and then use the .write() method to write each line to a new file. Here's an example:

  
  # Open the input file
with open("input.txt", "r") as infile:
    # Open the output file
    with open("output.txt", "w") as outfile:
        # Loop through each line in the input file
        for line in infile:
            # Write the line to the output file
            outfile.write(line)

This code will open the file "input.txt" in read mode, read its contents line by line, and write each line to a new file called "output.txt" in write mode. If the output file already exists, it will be overwritten. If you want to append the contents to existing file, open the file in "a" mode instead of "w" mode.


with open("input.txt", "r") as infile:
    with open("output.txt", "a") as outfile:
        for line in infile:
            outfile.write(line)

This code will open the input file in read mode, read its contents line by line, and append each line to a new file called "output.txt" in append mode. If the output file already exists, it will be preserved and new contents will be appended to it.

python read file line by line until eof

You can use a for loop to read a file line by line until the end of the file (EOF) is reached. Here's an example:


# Open the file
with open("example.txt", "r") as f:
    # Loop through each line in the file
    for line in f:
        # Print the line
        print(line)

This code will open the file "example.txt" in read mode, read its contents line by line, and print each line to the console until the end of the file is reached. The for loop will automatically stop iterating when there are no more lines left to read in the file.

You can also use f.readline() method, it will read one line of the file and return it as a string. It will return empty string at the end of the file.


with open("example.txt", "r") as f:
    line = f.readline()
    while line:
        print(line)
        line = f.readline()

This code will open the file "example.txt" in read mode, read one line of the file at a time and print it to the console until the end of the file is reached. The while loop will continue to execute until the return value of f.readline() is an empty string, indicating that the end of the file has been reached.

25 Best Online Criminal Justice Degree Programs [2023 Guide]

noreply@blogger.com (Nick) — Wed, 07 Dec 2022 11:41:00 +0000

Explore online Criminal Justice degree programs. Compare schools and see what you could be doing after you graduate.

A degree in Criminal Justice prepares you to work for the various levels of government in a wide range of roles. You could also work in the legal field.

Criminal Justice graduates earn between $52,000 and $126,000 a year (Bureau of Labor Statistics) depending on their job.

Types of Online Criminal Justice Degrees

Click on the area that interests you to jump to that part of the page.

While these areas are all related, each one will prepare you for a different career.

Criminal Justice

If you are the type of person who dreams of protecting the innocent and sending offenders behind bars, then you might pursue a degree in criminal justice.

This degree can help you learn what you need to know about the criminal justice system, particularly how its three major institutions—law enforcement, corrections system, and the courts—function.

Students are typically trained to develop strong leadership and management skills and how to be analytical and diplomatic.

Upon graduation, criminal justice majors can find a host of employment opportunities. You might be a cool FBI special agent. You may also work as a crime scene investigator, a probation officer, or a police detective.

Corrections

If you believe that criminal offenders should be given the opportunity to rehabilitate themselves, then you should consider getting a corrections degree.

You can not only get the chance to land a good-paying job but also test your conflict-resolution skills and even help convicts get back on the right track.

As you prepare yourself for work inside correctional facilities, common topics of study may include public safety and correctional methods. Most degrees in this field include training in conflict resolution skills, such as how to maintain your cool and composure, which can help you in enforcing rules.

Upon graduation, you will likely work in prisons or jails, but you may also find employment opportunities in private security firms and even hospital settings.

Crime Scene Investigation (CSI)

You’ve probably dreamt of becoming a crime scene investigator because of shows like CSI and NCIS. While the job is a lot more difficult than what TV often depicts, there is no denying that being a crime scene investigator is one of the more colorful jobs you can get.

The ideal candidate for a degree in CSI is analytical, organized, methodical, and hardworking. Common studies in CSI degrees include ethics, psychology, criminal justice, chemistry, physics, and legal studies.

Upon graduation, you can find employment opportunities in law enforcement agencies. You may also find work in private detective firms. Your education should prepare you for the rigors of the job, including being investigating disturbing crime scenes.

Aside from being physically fit, you must also be able to handle stressful working environments.

Emergency Management

Pursue a degree in emergency management if you dream of helping people during disasters such as tornadoes, wildfires, and storms.

You may also enjoy this field if you like helping people prepare for natural or man-made disasters.

With a degree in emergency management, you may find yourself working in public and private organizations such as the Department of Homeland Security and the Red Cross.

You may work as a firefighter, first aid responder, or an emergency systems specialist. As you gain more experience and earn the necessary education or accreditation, you may even take up more senior roles such as the emergency services system director.

Homeland Security

You may find a degree in homeland security worth taking if you have an interest in identifying, mitigating, and controlling national security risks.

While a homeland security degree can lead you to a job in law enforcement, it may also be your ticket to a job in criminal justice, emergency response, and cybersecurity, among others.

A homeland security degree program can help give you a strong foundation in areas such as intelligence, counter-terrorism, border security, and emergency management. Other common studies include training in cyber warfare, terrorist groups, and transnational security, among others.

Upon graduation, you are likely to find work in the federal government. One of the largest employers of homeland security degree holders is the Department of Homeland Security, with more than 240,000 employees. You may also find employment in law enforcement agencies, emergency management companies, and security firms.

A growing number of universities offer both on-campus as well as online homeland security degree programs.

Law Enforcement

You can help prepare yourself for a lucrative career in criminal justice by earning a degree in law enforcement.

With a law enforcement degree, you can gain the knowledge, training, and qualification to become a police officer, detective, or probation or parole officer, among others.

Some of the courses you’d likely take when pursuing a law enforcement degree are investigative techniques, modern policing, law enforcement operations, and criminal investigations.

Law enforcement degree candidates are trained to be analytical and organized. They are also expected to be physically fit and mentally tough.

Courses for an Online Criminal Justice Degree

The courses offered in an online criminal justice program differ depending on the school, educational path, and career goals of the students. However, below are some of the courses you are likely to take during the course of a criminal justice degree program:

Criminal Justice— provides a deeper understanding of criminal laws, courtroom procedures, and the criminal process from arrest, detention, and incarceration.
Victimology – discusses the experiences of victims as they move through the criminal justice system to give a better understanding of victimization patterns, among others.
Ethics and Diversity — discusses the ethical practice of law enforcement, particularly in incorporating cultural awareness in various communities.
Terrorism — gives a closer look at the behavior and motivations of terrorist groups as well as the effects of terrorist activities at local and national levels
Drugs and Crime — discusses the origins of drug addiction and how it is related to crime. Students also learn and analyze drug policies, drug treatment, and drug prevention programs.

You’ll also take classes specific to your concentration.

Criminal Justice Degree Salary

You may be surprised to learn that a criminal justice degree can open up a wide range of employment opportunities.

According to the Bureau of Labor Statistics, some careers in the criminal justice field include:

Careers	Annual Median Salary
Lawyer	$126,930
FBI Agent	$92,080
Detective and Criminal Investigator	$86,940
Arbitrator	$66,130
Police Officer	$65,540
Forensic Analyst	$60,590
Probation Officer	$55,690
Private Detective and Investigator	$53,320
Paralegal	$52,920

While education is the largest factor in determining your starting salary, performance and experience will be what moves you up in your organization.

Professional Organizations for Those with a Criminal Justice Degree

The criminal justice field has become quite competitive in recent years. Joining professional organizations can help criminal justice degree holders build their credentials and expand their network.

American Academy of Forensic Science – Founded in 1948, the American Academy of Forensic Sciences is a group of forensic science professionals based in Colorado, USA. It has members from more than 70 countries. It promotes professionalism, competency, and integrity in the forensic science field.
American Correctional Association – A private and non-profit trade group, the American Correctional Association is the oldest and largest trade association for the corrections industry. Founded in 1870, it had played a significant role in prison reform in the United States. An accrediting body, it has accredited more than 900 prisons, jails, and other correctional facilities in the US.
American Jail Association – The AJA offers a career resource for individuals looking to gain employment in the corrections field. This association has members from more than 3,500 jails and correctional institutions in the United States.
National Criminal Justice Association – This non-profit and non-partisan association has members from the law enforcement, corrections, academics, and justice communities.

Joining one or more of these organizations as a student can give you additional insights into the industry through publications, industry news, and job boards.

Accreditation for a Criminal Justice Degree Online

Accreditation is an important factor when searching for a criminal justice degree online. Consider enrolling in a college or university with a regional accreditation as this ensures that the institution provides quality education.

Employers also tend to give preference to candidates with criminal justice degrees from colleges and universities with regional accreditation.

US colleges and universities offering criminal justice programs may also have national accreditation, which is considered less prestigious than regional accreditation. Nationally-accredited schools, though, may offer more affordable criminal justice programs.

Financial Aid for a Criminal Justice Bachelors Degree Online

Some students apply for private or federal loans to help them finance their criminal justice education. If you take this route, you will have to repay your lender upon graduation.

You can also look and apply for scholarships and grants, which don’t have to be repaid. You’ll have to meet strict requirements to qualify, though, such as submitting an essay detailing your achievements and compelling reasons why you should be given the scholarship.

See what federal aid you qualify for by filling out the Free Application for Federal Student Aid (FAFSA).

You can then apply for private scholarships, including the Martin Luther King, Jr. scholarship, which is open to minority students currently enrolled or about to be accepted to an undergraduate criminal justice program.

You can also apply for a scholarship under the Melissa Linville Criminal Justice program, which benefits freshmen planning to major in criminal justice.

Other scholarships that you may want to try applying to are the Ritchie-Jennings Memorial Scholarships and the National Organization of Black Law Enforcement Executives (NOBLE) scholarships.

Questions Related to Earning a Bachelor Degree in Criminal Justice Online

Here are our answers to a few more questions you might have.

Can You Get a Criminal Justice Degree Online?

Yes, you can earn a Criminal Justice degree online. There’s a good number of colleges and universities across the country offering online criminal justice degrees.

Coursework for these programs is of the same quality as on-campus classes. You will also have the same professional opportunities as those who earn criminal justice degrees on-campus.

How Long Does It Take to Get a Criminal Justice Degree Online?

How long it takes to get a Criminal Justice degree online depends on the level of degree you want to take. You may earn a certificate program in criminal justice, which you can complete in 6 to 12 months. But this may not be enough to land you a job after graduation.

You may also take up an associate degree, which typically takes two years to complete. Bachelor’s and master’s degrees in criminal justice typically take 3-4 years.

As an alternate plan, you could explore programs that offer 4 week online college credit courses, which may help you to finish your degree faster.

How Much Does Criminal Justice Degree Cost?

How much a Criminal Justice degree costs depends on the level of degree you’ll be taking. An associate degree, which appeals to students who want to start a career in criminal justice in the shortest time possible, is the shortest to complete at 2 years on average.

The U.S. Department of Education says the average annual cost for an associate criminal justice degree is $21,141. Expect to spend at least $42,282 to complete this degree. Double that amount for a bachelor degree.

What Is the Best Online College for Criminal Justice?

The best online college for a criminal justice degree is one that is regionally-accredited.

You should also take into consideration other factors in choosing an online college for criminal justice degrees such as tuition fees, faculty longevity and credentials, and overall graduation rate.

What Are the Cheapest Online Criminal Justice Degree Programs?

You won’t have to pay thousands of dollars in tuition fees to get a criminal justice degree.

There are educational institutions offering affordable online criminal justice degree programs. Some of the most affordable degree programs cost just $200 per credit hour.

Universities Offering Criminal Justice Degrees Online

Methodology: The following school list is in alphabetical order. To be included, a college or university must be regionally accredited and offer degree programs online or in a hybrid format.

Arizona State University

Arizona State University offers a BS in Criminology and Criminal Justice. The program is a 120-credit-hour program with a total of 40 classes with each class lasting for 7.5 weeks.

Students who maintain a GPA of 3.40 and higher can apply to the accelerated criminal justice degree program, which can allow them to complete the BS and MA in just 5 years.

BS in Criminology and Criminal Justice

Arizona State University is accredited by the Higher Learning Committee.

Ball State University

Ball State University offers a BS in Criminal Justice and Criminology that has the unique feature of allowing you to customize your degree based on the career path you want to enter.

This program is ideal for persons working in criminology and criminal justice who wish to achieve their degree while juggling family and jobs.

BS in Criminal Justice and Criminology

BSU is accredited by the Higher Learning Commission.

Bellevue University

Bellevue University offers a BS in Criminal Justice and Emergency Management. The degree features a total of 127 credit hours and is offered on campus and online.

This is ideal for people who have deep-rooted values as justice, integrity, and honesty. Students can learn corrections, law enforcement, and court systems.

BS in Criminal Justice
BS in Emergency Management

Bellevue University is accredited by the Higher Learning Commission.

Bemidji State University

Bemidji State University offers a BS in Criminal Justice, which is provided partly online. The last two years of the BS are provided entirely online. Students pursuing this degree can choose to emphasize in Corrections, Law Enforcement, Victimology, and Tribal Justice.

The program is delivered entirely online, and there is the option to enroll for on-campus classes as well.

BS in Criminal Justice

Bemidji State University is fully accredited by the Higher Learning Commission.

Central Methodist University

Central Methodist University offers both a BA & BS in Criminal Justice. This program covers everything from profiling, serial crime, and American society law. Students get the opportunity to build the necessary skills for becoming a professional in the real world.

Courses covered include policing, criminal law, and the entire legal system.

BA in Criminal Justice
BS in Criminal Justice

CMU is accredited and/or recognized by the Higher Learning Commission.

Colorado State University

Colorado State University offers a Bachelor’s in Criminal Justice. This is a 120-credit-hour program that provides students with the knowledge and skills they need to perform in the criminal justice industry.

Students can learn law enforcement, managerial skills, and more to help with the smooth running of industry agencies.

Bachelor’s in Criminal Justice

Colorado State is accredited by The Higher Learning Commission.

Crown College

Crown College offers a BS in Criminal Justice as well as a BS in Disaster and Emergency Management. This degree is ideal for anyone who wants to join the growing and exciting field of criminal justice.

The program here is a Christ-centered one with a broad overview of criminal justice, giving students multiple entry points to start their career.

BS in Criminal Justice
BS in Disaster and Emergency Management

Crown College is accredited by the Higher Learning Commission.

Dallas Baptist University

Dallas Baptist University offers both a BA and a BS in Criminal Justice. Students of these programs are provided with a general scope of American crime and the criminal justice system.

Students enrolled in this program prepare for careers in the judicial system, in law enforcement, in corrections, juvenile justice, social services, and more.

BA in Criminal Justice
BS in Criminal Justice

Dallas Baptist University is accredited by the Southern Association of Colleges and Schools Commission on Colleges.

Drury University

Drury University offers three different options. There is a BS degree in Criminal Justice, one in Emergency Management, and One in Law Enforcement.

Students who are certain about which areas they want to pursue underneath the criminal justice umbrella may find these specific programs of interest. Students who are still unsure may find the Criminal Justice program ideal.

BS in Criminal Justice
BS in Emergency Management
BS in Law Enforcement

Drury University is accredited by the Higher Learning Commission.

Granite State College

Granite State College offers an online BS degree in Criminal Justice. The program is designed to prepare students to work in corrections, parole, advocacy, and probation roles, among others.

The program is unique in that it allows students to demonstrate their knowledge level and have this applied to their credit. Students who have work experience or volunteer-based experiences and training can earn credit hours for these.

BS in Criminal Justice

Granite State College is accredited by the New England Commission of Higher Education.

Liberty University

Liberty University offers a total of 9 online degrees that can help students prepare for a career in law enforcement, criminal justice, crime scene investigation, criminal psychology, and more.

Each degree program has a specific focus prepare students for particular jobs in a particular niche field of Criminal Justice.

BS in Criminal Justice – Business Administration and Management
BS in Criminal Justice – Crime Scence Investigation
BS in Criminal Justice – Criminal Psychology
BS in Criminal Justice – Homeland Security
BS in Criminal Justice – Juvenile Justice
BS in Criminal Justice – Public Administration
BS in Criminal Justice – Strategic Intelligence
BS in Law and Policy
BS in Law and Policy – Pre-Law

Liberty University is accredited by the Southern Association of Colleges and Schools Commission on Colleges.

Regent University

Regent University offers a BS in Criminal Justice along with a BS in Professional Studies with an emphasis. Programs are offered on campus as well as online.

The BS in Criminal Justice has a focus on homeland security, making it a perfect fit for students who want to get into careers in that field.

BS in Criminal Justice
BS in Professional Studies – Criminal Justice

Regent University is accredited by the Southern Association of Colleges and Schools Commission on Colleges.

Sam Houston State University

Sam Houston State University offers a BA in Criminal Justice and a BA in Homeland Security Studies. They also offer a BS in Criminal Justice and a BS in Homeland Security Studies.

These courses provide students the ability to study at research institutes. The program also allows students to access world-renowned correctional and law enforcement training.

BA in Criminal Justice
BA in Homeland Security Studies
BS in Criminal Justice
BS in Homeland Security Studies

Sam Houston State University is accredited by the Southern Association of Colleges and Schools Commission on Colleges.

Thomas Edison State University

Thomas Edison State University offers both a BA in Criminal Justice and a BS in Homeland Security and Emergency Management. These programs are suitable for adult learners and persons who have experience in law enforcement.

The program is designed to allow these people the opportunity to step up the career ladder.

BA in Criminal Justice
BS in Homeland Security and Emergency Management

Thomas Edison State University is regionally accredited by the Middle States Commission on Higher Education.

University of Central Florida

The University of Central Florida offers a BA and a BS degree in Criminal Justice. The programs are 120-credit-hour programs that are delivered entirely online. The program provides online, interactive coursework as well as hands-on training in some instances.

Students can learn the skills and knowledge they need to enter the various careers in the criminal justice system.

BA in Criminal Justice
BS in Criminal Justice

The University of Central Florida is accredited by the Southern Association of Colleges and Schools Commission on Colleges.

University of Mary

The University of Mary offers students a BS in Criminal Justice. The degree is offered entirely online and gives students the ability to take their criminal justice career to the next level. Students are allowed to transfer qualifying credits and can finish the program in as little as two years.

BS in Criminal Justice

The University of Mary is accredited by The Higher Learning Commission.

University of Maryland Global Campus

The University of Maryland Global campus offers a BS in Criminal Justice as well as a BS in Homeland Security. Both these programs are offered entirely online.

The programs give students the skills and knowledge they need to excel in a variety of careers in the field of Criminal Justice.

BS in Criminal Justice
BS in Homeland Security

UMGC is accredited by the Middle States Commission on Higher Education.

University of Massachusetts – Global

The University of Massachusetts Global offers a BA in Criminal Justice. The program is designed to expose students to real-life experiences. The program covers legal strategies, ethical strategies, and knowledge for problem-solving.

This is often a good choice for those interested in being able to fit into a wide variety of justice, court, and law enforcement careers.

BA in Criminal Justice

The University of Massachusetts Global is accredited by the WSCUC Senior College and University Commission.

University of Nebraska – Kearney

The University of Nebraska at Kearney campus offers a fully online BS degree in Criminal Justice. The degree is a 120-credit program that provides students with the necessary knowledge and skills for jobs in the criminal justice fields.

The degree is suitable for persons already working in the area as well as is ideal for new high school grads.

BS in Criminal Justice

The University of Nebraska at Kearney is accredited by the Higher Learning Commission.

University of Phoenix

The University of Phoenix offers online degrees including a BS in Correctional Program Support Services, a BS in Criminal Justice Administration and a BS in Security Management.

Each program has its definite focus, and as such, these degrees are ideal for students who know for a fact what fields they want to get into after school.

BS in Correctional Program Support Services
BS in Criminal Justice Administration
BS in Security Management

The University of Phoenix is regionally accredited by the Higher Learning Commission.

University of South Dakota

The University of South Dakota offers both a BA and a BS degree in Criminal Justice. The beauty of these programs is that they do not focus only on Criminal Justice

They include course material from other disciplines so that the program prepares students to work in a variety of segments of the criminal justice system.

BA in Criminal Justice
BS in Criminal Justice

The University of South Dakota is accredited by the Higher Learning Commission.

University of South Florida

The University of South Florida main campus offers a BA in Criminology along with a BS in Applied Sciences with an emphasis in Criminal Justice.

The degrees are offered partially online as they are completion courses. The BA has an internship program, which, of course, cannot be completed online. The BS program is a capstone program, so students must have an ASC to enroll.

BA in Criminology
BS in Applied Sciences – Criminal Justice

USF is accredited by the Southern Association of Colleges and Schools’ Commission on Colleges.

Washington State University

Washington State University offers a BA in Criminal Justice and Criminology. This program is well suited for those who have a keen interest in criminal behavior and want to make a difference in the ridding society of these plagues.

The BA program accepts students for summer and fall semesters annually.

BA in Criminal Justice and Criminology

Washington State University is accredited by the Northwest Commission on Colleges and Universities.

Western Carolina University

Western Carolina University offers BS degrees in Criminal Justice and Emergency and Disaster Management. This program is one of the largest at WCU.

Graduates have a lot of career opportunity options upon completing this program, and those already working the field can look forward to moving up the career ladder.

BS in Criminal Justice
BS in Emergency and Disaster Management

Western Carolina University is accredited by the Southern Association of Colleges and Schools Commission on Colleges.

Wilmington University

Wilmington University offers an online BS in Criminal Justice. The program is delivered by experience Criminal Justice instructors and provides relevant training for the field.

The degree is not a “one size fits all option,” with its variety in course content and direction. Students get the opportunity to visit criminal justice agencies and to meet some of the industry practitioners.

BS in Criminal Justice

Wilmington University is accredited by the Middle States Commission on Higher Education.

Is a Criminal Justice Degree Worth It?

Yes, a Criminal Justice degree is worth it for many students. The Bureau of Labor Statistics is projecting 3% job growth in protective service occupations over the next 10 years. Common careers in this sector include paralegal, probation officer, forensic analyst, detective and criminal investigator, and lawyer.

Earning a criminal justice degree is worth the time and effort as you have plenty of employment opportunities to choose from after graduation.

You can work not only for the government but also for private entities. In short, a criminal justice degree can be your ticket to a decent-paying and noble job in the future. Apply to universities and colleges offering online criminal justice programs now.

Python - Variable Types

noreply@blogger.com (Nick) — Fri, 25 Nov 2022 05:59:00 +0000

In the previous tutorial on Basic Data Types in Python, you saw how values of various Python data types can be created. But so far, all the values shown have been literal or constant values:

>>> print(5.3)
5.3

If you’re writing more complex code, your program will need data that can change as program execution proceeds.

Here’s what you’ll learn in this tutorial: You will learn how every item of data in a Python program can be described by the abstract term object, and you’ll learn how to manipulate objects using symbolic names called variables.

Free PDF Download: Python 3 Cheat Sheet

Variable Assignment

Think of a variable as a name attached to a particular object. In Python, variables need not be declared or defined in advance, as is the case in many other programming languages. To create a variable, you just assign it a value and then start using it. Assignment is done with a single equals sign (=):

>>> n = 300

This is read or interpreted as “n is assigned the value 300.” Once this is done, n can be used in a statement or expression, and its value will be substituted:

>>> print(n)
300

Just as a literal value can be displayed directly from the interpreter prompt in a REPL session without the need for print(), so can a variable:

>>> n
300

Later, if you change the value of n and use it again, the new value will be substituted instead:

>>> n = 1000
>>> print(n)
1000
>>> n
1000

Python also allows chained assignment, which makes it possible to assign the same value to several variables simultaneously:

>>> a = b = c = 300
>>> print(a, b, c)
300 300 300

The chained assignment above assigns 300 to the variables a, b, and c simultaneously.

Variable Types in Python

In many programming languages, variables are statically typed. That means a variable is initially declared to have a specific data type, and any value assigned to it during its lifetime must always have that type.

Variables in Python are not subject to this restriction. In Python, a variable may be assigned a value of one type and then later re-assigned a value of a different type:

>>> var = 23.5
>>> print(var)
23.5

>>> var = "Now I'm a string"
>>> print(var)
Now I'm a string

Object References

What is actually happening when you make a variable assignment? This is an important question in Python, because the answer differs somewhat from what you’d find in many other programming languages.

Python is a highly object-oriented language. In fact, virtually every item of data in a Python program is an object of a specific type or class. (This point will be reiterated many times over the course of these tutorials.)

Consider this code:

>>> print(300)
300

When presented with the statement print(300), the interpreter does the following:

Creates an integer object
Gives it the value 300
Displays it to the console

You can see that an integer object is created using the built-in type() function:

>>> type(300)
<class 'int'>

A Python variable is a symbolic name that is a reference or pointer to an object. Once an object is assigned to a variable, you can refer to the object by that name. But the data itself is still contained within the object.

For example:

>>> n = 300

This assignment creates an integer object with the value 300 and assigns the variable n to point to that object.

The following code verifies that n points to an integer object:

>>> print(n)
300
>>> type(n)
<class 'int'>

Now consider the following statement:

>>> m = n

What happens when it is executed? Python does not create another object. It simply creates a new symbolic name or reference, m, which points to the same object that n points to.

Next, suppose you do this:

>>> m = 400

Now Python creates a new integer object with the value 400, and m becomes a reference to it.

Lastly, suppose this statement is executed next:

>>> n = "foo"

Now Python creates a string object with the value "foo" and makes n reference that.

There is no longer any reference to the integer object 300. It is orphaned, and there is no way to access it.

Tutorials in this series will occasionally refer to the lifetime of an object. An object’s life begins when it is created, at which time at least one reference to it is created. During an object’s lifetime, additional references to it may be created, as you saw above, and references to it may be deleted as well. An object stays alive, as it were, so long as there is at least one reference to it.

When the number of references to an object drops to zero, it is no longer accessible. At that point, its lifetime is over. Python will eventually notice that it is inaccessible and reclaim the allocated memory so it can be used for something else. In computer lingo, this process is referred to as garbage collection.

Object Identity

In Python, every object that is created is given a number that uniquely identifies it. It is guaranteed that no two objects will have the same identifier during any period in which their lifetimes overlap. Once an object’s reference count drops to zero and it is garbage collected, as happened to the 300 object above, then its identifying number becomes available and may be used again.

The built-in Python function id() returns an object’s integer identifier. Using the id() function, you can verify that two variables indeed point to the same object:

>>> n = 300
>>> m = n
>>> id(n)
60127840
>>> id(m)
60127840

>>> m = 400
>>> id(m)
60127872

After the assignment m = n, m and n both point to the same object, confirmed by the fact that id(m) and id(n) return the same number. Once m is reassigned to 400, m and n point to different objects with different identities.

Deep Dive: Caching Small Integer Values

From what you now know about variable assignment and object references in Python, the following probably won’t surprise you:

>>> m = 300
>>> n = 300
>>> id(m)
60062304
>>> id(n)
60062896

With the statement m = 300, Python creates an integer object with the value 300 and sets m as a reference to it. n is then similarly assigned to an integer object with value 300—but not the same object. Thus, they have different identities, which you can verify from the values returned by id().

But consider this:

>>> m = 30
>>> n = 30
>>> id(m)
1405569120
>>> id(n)
1405569120
Here, m and n are separately assigned to integer objects having value 30. But in this case, id(m) and id(n) are identical!

For purposes of optimization, the interpreter creates objects for the integers in the range [-5, 256] at startup, and then reuses them during program execution. Thus, when you assign separate variables to an integer value in this range, they will actually reference the same object.

Variable Names

The examples you have seen so far have used short, terse variable names like m and n. But variable names can be more verbose. In fact, it is usually beneficial if they are because it makes the purpose of the variable more evident at first glance.

Officially, variable names in Python can be any length and can consist of uppercase and lowercase letters (A-Z, a-z), digits (0-9), and the underscore character (_). An additional restriction is that, although a variable name can contain digits, the first character of a variable name cannot be a digit.

Note: One of the additions to Python 3 was full Unicode support, which allows for Unicode characters in a variable name as well. You will learn about Unicode in greater depth in a future tutorial.

For example, all of the following are valid variable names:

>>> name = "Bob"
>>> Age = 54
>>> has_W2 = True
>>> print(name, Age, has_W2)
Bob 54 True

But this one is not, because a variable name can’t begin with a digit:

>>> 1099_filed = False
SyntaxError: invalid token

Note that case is significant. Lowercase and uppercase letters are not the same. Use of the underscore character is significant as well. Each of the following defines a different variable:

>>> age = 1
>>> Age = 2
>>> aGe = 3
>>> AGE = 4
>>> a_g_e = 5
>>> _age = 6
>>> age_ = 7
>>> _AGE_ = 8

>>> print(age, Age, aGe, AGE, a_g_e, _age, age_, _AGE_)
1 2 3 4 5 6 7 8

There is nothing stopping you from creating two different variables in the same program called age and Age, or for that matter agE. But it is probably ill-advised. It would certainly be likely to confuse anyone trying to read your code, and even you yourself, after you’d been away from it awhile.

It is worthwhile to give a variable a name that is descriptive enough to make clear what it is being used for. For example, suppose you are tallying the number of people who have graduated college. You could conceivably choose any of the following:

>>> numberofcollegegraduates = 2500
>>> NUMBEROFCOLLEGEGRADUATES = 2500
>>> numberOfCollegeGraduates = 2500
>>> NumberOfCollegeGraduates = 2500
>>> number_of_college_graduates = 2500

>>> print(numberofcollegegraduates, NUMBEROFCOLLEGEGRADUATES,
... numberOfCollegeGraduates, NumberOfCollegeGraduates,
... number_of_college_graduates)
2500 2500 2500 2500 2500

All of them are probably better choices than n, or ncg, or the like. At least you can tell from the name what the value of the variable is supposed to represent.

On the other hand, they aren’t all necessarily equally legible. As with many things, it is a matter of personal preference, but most people would find the first two examples, where the letters are all shoved together, to be harder to read, particularly the one in all capital letters. The most commonly used methods of constructing a multi-word variable name are the last three examples:

Camel Case: Second and subsequent words are capitalized, to make word boundaries easier to see. (Presumably, it struck someone at some point that the capital letters strewn throughout the variable name vaguely resemble camel humps.)
- Example: numberOfCollegeGraduates
Pascal Case: Identical to Camel Case, except the first word is also capitalized.
- Example: NumberOfCollegeGraduates
Snake Case: Words are separated by underscores.
- Example: number_of_college_graduates

Programmers debate hotly, with surprising fervor, which of these is preferable. Decent arguments can be made for all of them. Use whichever of the three is most visually appealing to you. Pick one and use it consistently.

You will see later that variables aren’t the only things that can be given names. You can also name functions, classes, modules, and so on. The rules that apply to variable names also apply to identifiers, the more general term for names given to program objects.

The Style Guide for Python Code, also known as PEP 8, contains Naming Conventions that list suggested standards for names of different object types. PEP 8 includes the following recommendations:

Snake Case should be used for functions and variable names.
Pascal Case should be used for class names. (PEP 8 refers to this as the “CapWords” convention.)

Reserved Words (Keywords)

There is one more restriction on identifier names. The Python language reserves a small set of keywords that designate special language functionality. No object can have the same name as a reserved word.

In Python 3.6, there are 33 reserved keywords:

Python Keywords
`False`	`def`	`if`	`raise`
`None`	`del`	`import`	`return`
`True`	`elif`	`in`	`try`
`and`	`else`	`is`	`while`
`as`	`except`	`lambda`	`with`
`assert`	`finally`	`nonlocal`	`yield`
`break`	`for`	`not`
`class`	`from`	`or`
`continue`	`global`	`pass`

You can see this list any time by typing help("keywords") to the Python interpreter. Reserved words are case-sensitive and must be used exactly as shown. They are all entirely lowercase, except for False, None, and True.

Trying to create a variable with the same name as any reserved word results in an error:

>>> for = 3
SyntaxError: invalid syntax

Conclusion

This tutorial covered the basics of Python variables, including object references and identity, and naming of Python identifiers.

You now have a good understanding of some of Python’s data types and know how to create variables that reference objects of those types.

Next, you will see how to combine data objects into expressions involving various operations.

How to install Python on Ubuntu 20.04 LTS?

noreply@blogger.com (Nick) — Wed, 23 Nov 2022 15:00:00 +0000

How to install Python on Ubuntu 20.04 LTS?

Introduction

Python is a high level, dynamic and general purpose programming language. It was designed and developed by Python Software Foundation.

Python is a cross-platform language and was first released on 20, February 1991.

In this tutorial, we are working on the installation process of Python that includes the following steps.

Although Python 2.7 is installed by default in Ubuntu, but we can install other Python versions like python3.

To install python3, just type the following command in the terminal and it will be installed automatically.

Python Installation

1) Update the APT Repository

$ apt-get update

2) Install Python

$ apt-get install python3.6

2) Verify Python

When we type python it shows default installed python that is 2.7.

$ python

For Python3 type the following command, then it will show the other version as well.

$ python3

Well, on the basis of these commands, we can test application for both Python versions.

Installation on Mac

To install python3 on MacOS, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python3-on-macos.html and follow the instructions given in the tutorial.

Installation on CentOS

To install Python3 on CentOS, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-3-on-centos.html and follow the instructions given in the tutorial.

Installation on Windows

To install Python3 on Ubuntu, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-on-windows.html and follow the instructions given in the tutorial.

How to Install Python 3 on CentOS

noreply@blogger.com (Nick) — Wed, 23 Nov 2022 14:59:00 +0000

How to Install Python 3 on CentOS

Introduction

Python is a high level, dynamic, general purpose language. It was developed by Guido Van Rossum in 1991. Python's syntax allows developers to use fewer lines of code than any other programming language. It basically focuses on the code readability of program. Python 2.7 is installed by default on CentOS but we can install other versions like Python 3.9 and 3.10 . In this tutorial, we are learning how to install Python 3.6.3 on CentOS.

Prerequisites

CentOS
Login as an administrator on the terminal
Yum must be configured on the system.

Installation

Installation includes following steps.

1. Install IUS community Repository

In order to install Python 3.6 on CentOS, we need to first install IUS community repository which provides extra packages for Enterprise Linux. Execute the following command to install IUS community repository.

$ sudo yum -y install https://centos7.iuscommunity.org/ius-release.rpm

2. Install Python 3

Execute the following command to install python 3.6 on CentOS.

$ sudo yum install python36u

3. Verify Python

To verify if we have installed correct version of python, we just need to type python3.6 -V on the terminal. The command will show the version installed which is 3.6.4 in my case.

4. Working on Python's script mode

Just type python3.6 on the terminal to enter the Python's script mode. We can execute the python statements on this shell. Since, python 2 is by default installed on CentOS, hence typing python on the terminal takes us to the python2 shell, hence we have to type python3.6 to work on the desired python shell.

Execute the valid python statements which get interpreted and show the desired output on the terminal as shown below.

Hence, we have installed and get started with Python 3.

Installation on MacOS

To install python3 on MacOS, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python3-on-macos.html and follow the instructions given in the tutorial.

Installation on Windows

To install Python3 on CentOS, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-on-windows.html and follow the instructions given in the tutorial.

Installation on Ubuntu

To install Python3 on Ubuntu, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-on-ubuntu-2004-lts.html and follow the instructions given in the tutorial.

How to Install Python3 on MacOS

noreply@blogger.com (Nick) — Wed, 23 Nov 2022 14:57:00 +0000

How to Install Python3 on MacOS

Introduction

Python is a high level, dynamic, general purpose language. It was developed by Guido Van Rossum in 1991. Python's syntax allows developers to use fewer lines of code than any other programming language. It basically focuses on the code readability of program. Python 2.7 is installed by default on MacOS but we can install other versions like python 3.5 and 3.6.

In this tutorial, we are learning how to install Python 3.6.3 on the MAC Operating system.

Prerequisites

MacOS
Login as an administrator on terminal

Installation

There are following steps which are used while installing Python3 on MacOS.

1) Checking python's version on the system

We can check which version of the Python is currently installed on our system. Generally, Python 2.7 is installed by default.

Let's see how can we do it.

$ python -version

It shows Python 2.7.10 is installed on the computer which is quite often.

2) Download Python 3.6.3

In order to install Python 3.6.3, we must download the latest version from its official website https://www.python.org/downloads/ . The file is downloaded in .pkg format which can be directly installed by using Installer command.

3) Install Python 3.6.3

Since the downloaded file already is in .pkg format hence no mounting is required and We can use installer command to install Python 3.6.3.

Let's see how can we do it.

Since The installer is used with super user permissions hence sudo forces terminal to prompt the user to fill the admin password. The process installs the Python 3.6.3 to the root directory which is mentioned with the target option.

4) Verify Python3

To check which Python version is installed on the machine, we can use python -version command. Since by default installed version is Python 2.7.10 hence it shows python 2.7.10. but it gives us flexibility to check the version of Python 3 on our computer.

Let's see how can we use python 3 to check which version of python 3 is running.

$ python -version

5) Working on Python's script mode

To work on Python command line, we simply type python3 on the terminal. Python shell open where we can run Python statements such as print statements as we did here.

To run a Python file (.py) on the terminal, we simply type the file name and the file will be interpreted.

Well, we have installed Python3 on our MacOS.

Installation on Windows

To install python3 on Windows OS , visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-on-windows.html and follow the instructions given in the tutorial.

Installation on CentOS

To install Python3 on CentOS, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-3-on-centos.html and follow the instructions given in the tutorial.

Installation on Ubuntu

To install Python3 on Ubuntu, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-on-ubuntu-2004-lts.html and follow the instructions given in the tutorial.

How to Install Python on Windows (Environment Set-up)

noreply@blogger.com (Nick) — Wed, 23 Nov 2022 14:55:00 +0000

How to Install Python (Environment Set-up)

In order to become Python developer, the first step is to learn how to install or update Python on a local machine or computer. In this tutorial, we will discuss the installation of Python on various operating systems.

Installation on Windows

Visit the link https://www.python.org/downloads/ to download the latest release of Python. In this process, we will install Python 3.8.6 on our Windows operating system. When we click on the above link, it will bring us the following page.

Step - 1: Select the Python's version to download.

Click on the download button.

Step - 2: Click on the Install Now

Double-click the executable file, which is downloaded; the following window will open. Select Customize installation and proceed. Click on the Add Path check box, it will set the Python path automatically.

We can also click on the customize installation to choose desired location and features. Other important thing is install launcher for the all user must be checked.

Step - 3 Installation in Process

Now, try to run python on the command prompt. Type the command python -version in case of python3.

We are ready to work with the Python.

Installation on Mac

To install python3 on MacOS, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python3-on-macos.html and follow the instructions given in the tutorial.

Installation on CentOS

To install Python3 on CentOS, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-3-on-centos.html and follow the instructions given in the tutorial.

Installation on Ubuntu

To install Python3 on Ubuntu, visit the link https://coderpad.blogspot.com/2022/11/how-to-install-python-on-ubuntu-2004-lts.html and follow the instructions given in the tutorial.

How to Kill Zombie Processes in Ubuntu

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:16:00 +0000

A zombie or a defunct process in Linux is a process that has been completed, but its entry still remains in the process table due to a lack of correspondence between the parent and child processes. Usually, a parent process keeps a check on the status of its child processes through the wait() function. When the child process has finished, the wait function signals the parent to completely exit the process from the memory. However, if the parent fails to call the wait function for any of its children, the child process remains alive in the system as a dead or zombie process. These zombie processes might accumulate, in large numbers, on your system and affect its performance. In that case, you might have to kill these zombies manually through the ways and commands described in this tutorial.

This tutorial is compatible with all recent Ubuntu versions including Ubuntu 22.04.

Viewing Zombie Processes

You can check your system�s performance by looking at the various processes running on your system, including efficiency-altering zombie processes. Ubuntu allows you to view these processes in the following way:

Through the Graphical User Interface
Through the Command Line

Through the GUI

In order to graphically view any zombie processes running on your system, open the System Monitor utility through your Ubuntu Dash. In the following screenshot of my System Monitor, you can view that there are two zombies running on my system. It is also possible that the number of zombie processes on your system might be less or more than the ones running on mine.

Through the Command Line

The top command displays a detailed view of the processes running on your system along with the memory and CPU resources they are using. It also gives you information about any zombie processes running on your system. Open the Terminal by pressing Ctrl+Alt+T and then type top. I got the following output after running this command.

$ top

You can see in the second line that there is 1 zombie process running on my system.

If you want further details about the zombie process, use the following command:

$ ps axo stat,ppid,pid,comm | grep -w defunct

This command will give you the state, parentID, the process ID, the program that is running the zombie process(a dummy program by the name �zombie� on my system). The defunct flag tells you that this is a dead, zombie process.

Killing a Zombie-Process

First, let us understand how zombie processes are a threat to our system�s performance. It is important to learn that zombies are dead and mostly complete processes that do not take memory or CPU resources. However, each of these processes has a unique process ID assigned to them which comes from a limited pool of PIDs reserved for your processor. If a large number of zombies gather, they will eat up most part of the PID pool and the new processes will not be able to launch due to the lack of a process ID.

A small number of defunct programs occupying your system is not a big threat but that means that their parent programs have not been able to call them off due to a bug or a missing wait() function.

When a parent process has not been able to call the wait() function automatically, we need to manually signal the parent process to run the wait function on all its children so the ones with a complete state can be called back. We can do this by running the SIGCHLD command. When that doesn�t work, we can manually kill the parent process so that all its zombie children are also killed, freeing the process IDs for the new processes.

You can kill the zombie processes through the following ways:

Through the Graphical User Interface
Through the Command Line

Through the GUI

You can kill a zombie process graphically through the System Monitor Utility as follows:

Open the System Monitor utility through Ubuntu Dash.
Search for the term Zombie through the Search button.
Select the zombie process, right-click and then select Kill from the menu.

The zombie process will be removed from your system.

Through the Command Line

After you know that there are any zombie processes running on your system through the top command. This is how to view the details of the processes.

The usual way is to use the following command that signals the zombie�s parent process to kill the command.

$ kill -s SIGCHLD PID

This command may not work in a few cases as not all parent processes are programmed properly in order to check upon the child processes. In that case, you can kill the parent process through the following command:

$ sudo kill -9 3376

When you have killed all the zombie processes this way and run the top command, you will be able to see that there are no zombie processes running on your system anymore:

After working along with this tutorial, you can optimize your operating system by looking for any zombie processes on your system and killing them manually through the command line or the graphical user interface. This act will free up process IDs for the new processes that you want to run on your system.

How to Kill Zombie Processes in Ubuntu

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How to Install LAMP Stack on Linux Mint

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:15:00 +0000

Installing Apache requires the installation of a complete LAMP package (Linux, Apache, MySQL and, PHP). To do development, users require a complete set of these open-source software and a locally set up machine before they can host their websites to test it out.� We will go through the complete installation of the LAMP stack on Linux Mint 20.

Updating the Linux mint 20 system

The first step is to update the OS by running the following command through the terminal window:

$ sudo apt-get update

The system will prompt to enter the password.

Now, check for the available apt updates and get them in the Linux system using:

$ sudo apt-get upgrade

Next, update the packages using the following command:

$ sudo apt-get dist-upgrade

This upgrade might take some time. Once done, you need to reboot the system to get the updates done using:

$ sudo reboot

Installation of the LAMP server

After that, install the LAMP server in the system. Type the command given below to start the process of installation:

$ sudo apt-get install lamp-server^

You need to end it with the caret (^). The system will prompt and ask for the permission of the user. Append Y and then press enter from the keyboard.

Testing the installation of Apache webserver

Apache is the webserver of the LAMP stack and once installed to confirm the installation type the following in the terminal window:

$ sudo systemctl status apache2

This command will tell whether Apache is running or not. If you see an output like this one then it means it is installed correctly.

We can also check the installation confirmation from the browser. Type http://localhost on the window of your browser. Once done, you will see an output like the one shown below. It will confirm that the Apache server is installed correctly. You can add more web pages. Apache2 web page runs in the path /var/www/html.

To update the content, make changes in the index.html page.

Testing the installation of PHP

PHP is the scripting language used in the LAMP stack. Now we need to verify the installation of PHP by creating a file info.php in /var/www/html path.

$ sudo nano /var/www/html/info.php

The nano text editor will open up an empty file info.php, type the following script in the file. and then press Ctl+O to save the file. To exit use Ctl+X.

<?php phpinfo(); ?>

Once done, restart the Apache2 server to ensure that the changes have been done.

Type http://localhost/info.php in the browser window. If PHP is installed correctly and output like this one will appear. This output will have the information about the Linyx environment and has configuration files.

Setting up MySQL root password

Go to the terminal and then log in to MySQL. Set up the password and then exit it.

Enter the command:

$ sudo mysql -u root

The terminal has now changed the prompt sign from $ to <. This means users have entered mysql and can make changes in the database.

Once updates have been done, type quit

Now, restart MySQL to save any changes made (like password) etc by using:

$ sudo systemctl restart mysql

Installing phpMyAdmin

MySQL command line is the tool for people who have hands-on experience of MySQL commands. On the other hand, PhpMyAdmin is GUI based method for the management of different databases. It is not part of our LAMP stack but is used to manage MySQL database. Return to the terminal window and use this command to install phpMyAdmin:

$ sudo apt-get install phpMyAdmin

Press the enter key when prompted. You need to press spacebar from the keyboard to select apache2.

Once you have selected the web server, the system will ask for your permission to configure the database. Press the enter key from the keyboard to choose Yes.

Users will then be prompted to provide phpMyAdmin password. Provide the password then confirm the password in the next dialogue box.

Once you have provided the password, you need to confirm it. Renter the password and then hit enter. The process of installation will continue.

Accessing PhpMyAdmin portal

To access PhpMyAdmin, type localhost/phpmyadmin. This will open up the login page. Provide the credentials and continue. The password is the one that was set earlier.

After you have logged in to phpmyadmin dashboard you can create and manage all databases.

Uninstalling Apache from the system

To uninstall Apache, simply type the following command in the system:

dpkg-l *apache* *mysql* phpmyadmin | grep ^ii | awk '{print $2 }' | xargs sudo apt-get -y purge --auto-remove

The uninstallation will begin similar to the one given below:

Conclusion

The tutorial covered the entire method of installation of the Apache web server. We tested the entire LAMP stack in the system and executed the testing for each of the steps. At last, we tested it on PhpMyAdmin and then went through the method of uninstallation of the system.

How to Install LAMP Stack on Linux Mint

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How to Create Aliases for Customizing Commands in Ubuntu 22.04

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:14:00 +0000

With Ubuntu, you can customize your long Bash commands by using short and pleasant aliases as replacements. When working on the command line, you can simply use an alias in place of the entire command you don�t want to type. The alias works exactly like the command it was created for.

In this tutorial, you will learn how to create and use an alias for a command in Ubuntu. We use a simple example to demonstrate this process to you. We will perform the steps and commands described in this article on an Ubuntu 22.04 system.

Example: Setting up an alias for the ��sudo apt-get install � command

If you do a lot of installations on your system and wish to avoid using the entire sudo apt-get install command, you can create a short alias for it using the following method:

Through the file manager, open the .bashrc file located in your home folder. This file is usually a hidden file so you will need to use the Ctrl+H control to view all the hidden files located in the folder. You can use your favorite text editor through the command line or UI to edit this file. We are using the default graphical text editor to open and edit this file.

Move to the end of the file and paste the following line:

alias agi='sudo apt-get install'

Here �agi� is the new alias we are setting up.

Syntax for creating an alias:

alias [aliasName]=�old_command'

You can also add other aliases to customize your apt-get commands by adding the following lines to this file:

alias agr='sudo apt-get remove'

alias agu='sudo apt-get update'

alias acs='apt-cache search'

Save the file by clicking the Save button located at the top right corner.

Open the Terminal through Ubuntu Dash or by pressing Ctrl+Alt+T

Run the following command in order to start using the new bashrc file.

$ source ~/.bashrc

The new .bashrc file is installed every time you log out and then log in. The above command enables you to use the changes without restarting your system.

The alias has been set-up; you can now run the following command in order to install a new package to your system:

$ agi [package name]

Example:

$ agi nautilus-admin

Instead of

$ sudo apt-get install nautilus-admin

You can see how in the above image I was able to install Nautilus by using the new command alias that I set up in this example.

Points to consider

While creating an alias please note the following points:

You cannot use an already existing command as an alias name. If you do this, your alias will not work, instead, the default ubuntu command will be executed.
The alias name cannot contain any spaces. If the new alias you want to set up contains two or more words, you can use the �-� character to separate those words.

Now you can get rid of the dry and rugged bash commands and use your own customized aliases to run the frequently used operations.

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How to use the Linux mtr (My Traceroute) command

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:13:00 +0000

What is the mtr command?

Mtr (my traceroute) is a command-line network diagnostic tool that provides the functions of the ping and traceroute commands. It is a simple and cross-platform tool that outputs information about the entire route that network packets take from the host system to the specified destination system. The mtr command is superior to the traceroute command because it also outputs the response percentage and response times for all network hops between the two systems.

As a network administrator, you must know how to use the mtr command and the flags that you can use to customize the output in order to perform productive network diagnostics. This article explains the use of the mtr command in detail and provides examples to show you how to use specific flags with this command.

We have run the commands and procedures described in this article on an Ubuntu 20.04 and Ubuntu 22.04 LTS system, but it should work on Debian 11 as well.

Since mtr is a command-line program, we will use it in the Ubuntu command line, the terminal. You can open the terminal application using either the System Dash or the key combination Ctrl +Alt+t.

Installing mtr Command

The mtr command is probably not installed as a default on your system. you can install it easily with apt though.

sudo apt install mtr

Usage of the mtr Command

1. View traceroute report in real-time

The mtr command is primarily used to display the traceroute report for a remote machine. All you have to do is enter the domain name or IP address of the remote system using the mtr command and the output will display the traceroute report in real-time. When you�re done viewing the report, you can exit the command with either q or the Ctrl+C key combination.

Display Hostnames

The following syntax of the mtr command displays the hostnames in the traceroute report.

Syntax:

$ mtr [domainName/IP]

Example:

$ mtr google.com

Display Numeric IP addresses

When you use the g flag with the mtr command, it displays the numeric IP addresses instead of the hostnames in the traceroute report.

Syntax:

$ mtr -g [domainName/IP]

Example:

$ mtr -g google.com

Both hostnames and numeric IP addresses

When you use the b flag with the mtr command, it displays both the numeric IP addresses and the hostnames in the traceroute report.

Syntax:

$ mtr -b [domainName/IP]

Example:

$ mtr -b google.com

2. Specify a limit for the number of pings

You can configure the mtr command to quit after printing the traceroute report for a specific number of pings. In the output, you can easily view the number of pings under the Snt column; when Snt reaches the number you specified in your command through the c flag, mtr will automatically exit.

Syntax:

$ mtr -c [n] �domainname/IP�

Example:

$ mtr -c 10 google.com

3. Enable Report Mode

Instead of printing the output of the mtr command on the screen, you can enable the report mode that will instead print the output in a text file. This way you can record the network analysis for later use and observation. All you need to do is enable the report mode through the r flag, specify a ping count for which you want to limit the report through the c flag, and also specify the report filename in which the report will be saved.

Syntax:

$ mtr -r -c [n] �domainname/IP� >�report-name�

Example:

$ mtr -r -c 10 google.com >mtr-report-google

The report is saved in the current user�s home folder by default. You can, however, specify a proper path for the report to be saved in.

Clear output in Report

Adding a w flag with the r flag will enable mtr to print a rather clear and more readable report for the traceroute.

Syntax:

$ mtr �rw -c [n] �domainname/IP� >�report-name�

Example:

mtr -rw -c 10 google.com >mtr-report-google

4. Rearrange the output fields

When you see the output of the mtr report, you will observe that the columns are arranged in a specific default manner. The o flag enables you to re-arrange the output in a customized manner to make it more useful and productive.

Syntax:

$ mtr -o �[Output Format]� �domainname/IP�

The mtr manpage can help you with what options you have while customizing the mtr report columns.

Example:

$ mtr -o "LSDR NBAW JMXI" google.com

5. Specify Time Interval between ICMP ECHO requests

Although the default time interval between each ICMP and ECHO request is 1 second in the mtr command, you can change it by using the i flag to specify a new time interval.

Syntax:

$ mtr -i [time-in-seconds] �domainName/IP�

Example:

$ mtr -i 10 google.com

6. Use TCP SYN packets or UDP datagrams

If you want to use the TCP SYN or the UDP datagrams for requesting mtr instead of the default ICMP ECHO requests, you can do so by using the tcp and udp flags respectively.

Syntax:

$ mtr �tcp �domainName/IP�

$ mtr �udp �domainName/IP�

Example:

$ mtr --tcp google.com

$ mtr --udp google.com

7. Specify the maximum number of hops between the local system and the remote machine

You can customize the maximum number of hops to be probed between your local system and the remote machine by specifying the time, in seconds, with the m flag. The default time limit between two hops is 30 seconds for the mtr command.

Syntax:

$ mtr -m [timeInSeconds] �domainName/IP�

Example:

$ mtr -m 35 216.58.223.78

8. Specify packet size

Through the s flag in the mtr command, you can specify the size, in bytes, of the IP packet for diagnosing network quality.

Syntax:

$ mtr �r -s [packetsize] �domainName/IP�

Example:

mtr -r -s 50 google.com

9. Print CSV Output

The CSV output of the mtr report delimits the columns with a �,�. With the csv flag, you can customize the mtr command to output the report in a CSV format.

Syntax:

$ mtr �csv �domainName/IP�

Example:

$ mtr --csv google.com

10. Print XML Output

The mtr command can also support the XML format for printing traceroute reports. The XML report is a good option for automated processing of the output and can be printed by specifying the xml flag with the mtr command.

Syntax:

$ mtr �xml �domainName/IP�

Example:

$ mtr --xml google.com

11. Accessing the mtr help and man page

Finally, you can get further options for usage and customization of the mtr command by reading its help and man page through the following commands.

$ man mtr

$ mtr --help

Here is a list of all mtr command-line options

Usage:
mtr [options] hostname

-F, --filename FILE read hostname(s) from a file
-4 use IPv4 only
-6 use IPv6 only
-u, --udp use UDP instead of ICMP echo
-T, --tcp use TCP instead of ICMP echo
-I, --interface NAME use named network interface
-a, --address ADDRESS bind the outgoing socket to ADDRESS
-f, --first-ttl NUMBER set what TTL to start
-m, --max-ttl NUMBER maximum number of hops
-U, --max-unknown NUMBER maximum unknown host
-P, --port PORT target port number for TCP, SCTP, or UDP
-L, --localport LOCALPORT source port number for UDP
-s, --psize PACKETSIZE set the packet size used for probing
-B, --bitpattern NUMBER set bit pattern to use in payload
-i, --interval SECONDS ICMP echo request interval
-G, --gracetime SECONDS number of seconds to wait for responses
-Q, --tos NUMBER type of service field in IP header
-e, --mpls display information from ICMP extensions
-Z, --timeout SECONDS seconds to keep probe sockets open
-M, --mark MARK mark each sent packet
-r, --report output using report mode
-w, --report-wide output wide report
-c, --report-cycles COUNT set the number of pings sent
-j, --json output json
-x, --xml output xml
-C, --csv output comma separated values
-l, --raw output raw format
-p, --split split output
-t, --curses use curses terminal interface
--displaymode MODE select initial display mode
-g, --gtk use GTK+ xwindow interface
-n, --no-dns do not resolve host names
-b, --show-ips show IP numbers and host names
-o, --order FIELDS select output fields
-y, --ipinfo NUMBER select IP information in output
-z, --aslookup display AS number
-h, --help display this help and exit
-v, --version output version information and exit

After reading this article, you are better equipped with running network diagnostics between your machine and a remote system. You also have an alternative to the ping and traceroute commands, with many more customization options for better productivity and usefulness.

How to use the Linux mtr (My Traceroute) command

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How to Format a USB drive in Ubuntu

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:12:00 +0000

It happens every now and then that we need to format a USB drive to change the file system, delete the data completely or get rid of a virus that has infected it. There are several ways to format a USB drive, and we�ve listed a few of them in this article so you can see which one works for you. You can format a USB drive both from the command line and from the graphical user interface, whichever you prefer.

Format USB Drive Through the Command Line

Formatting a USB drive is very easy via the command line. Even a beginner can format a USB drive using the commands described here.

1. the first step is to identify the USB drive correctly to avoid formatting another drive by mistake. Open the Terminal application via Dash or the Ctrl+Alt+T key combination and type the following command:

$ df -h

The last line in the output lists /dev/sdb1 as our USB drive.

2. Use the following command in order to format the USB as per the VFAT file system:

$ sudo mkfs.vfat /dev/sdb1

You will be using the location as per the output you got from the df -h command.

3. You can only format an unmounted USB drive, otherwise, you will get the following message:

Therefore, please unmount the drive through the following command:

$ sudo umount /dev/sdb1

Now when you run the formatting command as a root user, your USB drive will be successfully formatted.

Format USB Drive Through the GUI

Format Directly from the File Manager

You can format a USB drive through the graphical interface of your Ubuntu system as follows:

1. Open the file manager and then right-click the USB drive name that you want to format, from the left pane.

2. Click the Format option from the right-click menu. The following dialog will open.

3. Enter a volume name for your USB drive. In the figure above we have entered USB as the volume name.

You can delete the existing data on your USB drive by clicking the Delete button. In this case the existing data on your system will be overwritten and the formatting process will take a little longer. You can also specify the file system you want the USB drive to have. 4.

4. Click the Next button in the upper right corner, which becomes active only after you have entered all the details.

The following Confirm Details dialog will open so you can confirm the formatting details. Please make sure you format the correct volume by looking at the location information. This will prevent you from formatting an unwanted storage and damaging your system.

4. Click the Format button after confirming the details.

Your USB drive will be formatted and ready for use, based on the volume name, file system, and data erasing options you specified.

Format USB Drive through the GParted tool

You can also format your USB drive through a tool called Gparted. Gparted in an open source partition editor for Linux systems. Follow these steps to install and use this tool:

Installation

1. Open the Terminal through CTRL+ALT+T or through your Ubuntu Dash.

2. Enter the following command in order to install the open-source tool GParted:

$ sudo apt-get install gparted

3. Enter y when prompted by a y/n option for continuing installation.

The GParted tool will be installed on your system.

Formating

4. In order to access the GParted from your desktop, search for it through the Dash as follows:

5. Click on the GParted icon to open the application.

6. You will be asked to provide authentication for root user as only a root user can access and use this application. Provide the password and then click Authenticate.

The tool will open, displaying the /dev/sda partitions of the hard disk by default.

7. Since we want to view details of removable media, select that from the drop-down option located at the top-right corner. You will now be able to see the partitions of removable media as follows:

8. You need to unmount a USB drive before formatting it. Select the USB partition that you want to format, right-click and then click Unmount.

9. Now when you right-click the USB partition, the �Format to� option will become active. Click the Format to option and then select a file system you want to use for your USB drive.

We have selected ntfs in this example. This operation will be added as a pending operation.

10. In order to apply this operation, click the tick icon from the top bar to apply all operations.

11. The following dialog will appear, asking you for confirmation about applying all the pending operations. Click the Apply button when you are sure about your choice.

The formatting process will begin:

You will be notified when the operations have been completed as follows:

12. Click the Close button; you now have a formatted USB drive with the file system you specified.

After reading this article, you may have found a way to format your USB drive for better use. You can use both the command line and the user interface to format a USB drive after you unmount it. The powerful partition editing tool GParted will also help you format your drive based on a long list of file types.

How to Format a USB drive in Ubuntu

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How to Install AWS-CLI on Ubuntu

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:11:00 +0000

Since Linux users are more comfortable working with command line interfaces, Amazon Web Services introduced the AWS CLI to manage all these services from a single platform. With this tool, you can manage multiple services at once, easily and conveniently. In this guide, we�ll show you how to install the AWS CLI on Ubuntu Linux.

Install the AWS CLI on Ubuntu

In order to install the AWS CLI on an Ubuntu server or Desktop, you need to proceed with the following steps:

Step # 1: Prepare the Target Machine for the AWS CLI Installation

First, you need to prepare your target machine for the AWS CLI installation by updating it as shown below:

$ sudo apt-get update

This command will not only update the required packages but will also remove all the unnecessary ones.

Step # 2: Install the AWS CLI on the Target Machine

Then, you can install the AWS CLI on your target machine by running the following command:

$ sudo apt-get install awscli

Step # 3: Confirm the installation of the AWS CLI on the Target Machine

After that, you can confirm the installation of the AWS CLI on your target system by executing the command shown below:

$ aws --version

The appearance of the AWS CLI version on the terminal confirms its installation on the target machine as shown in the following image:

Remove the AWS CLI

To remove the AWS CLI along with all of its associated packages from your target system, you can simply run the command shown below:

$ sudo apt-get purge --autoremove awscli

Conclusion

The installation of the AWS CLI Ubuntu Linux and Linux Mint is extremely simple as we have seen in this article. Once you have this tool installed on your target system, you can conveniently manage as many Amazon Web Services as you want with the help of this unified tool.

�

How to Install AWS-CLI on Ubuntu

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How to Change sudo Password in Ubuntu 22.04

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:10:00 +0000

If you are a new Ubuntu admin user, you may want to know how to change the password in Ubuntu Linux Server from the bash shell or command line. After all, it is a good security practice to change passwords for every user, especially the SuperUser who can perform all sensitive operations in Ubuntu. Only a SuperUser or root can change the password for any user account. Other users can only change their own passwords.

User passwords are changed in Ubuntu using the passwd command.

In this article, we explain how a root user can change their own password on an Ubuntu server.

We have run the commands and procedures mentioned in this article on an Ubuntu 22.04 LTS system.

Need help in creating a strong password? Then take a look here: 7 Methods to Generate a Strong Password in Ubuntu

Step 1: Open the Ubuntu command line

We need to use the Ubuntu command line, the Terminal, in order to change the sudo password. Open the Terminal either through the system Dash or the Ctrl+Alt+T shortcut.

Step 2: Log in as root user

Only a root user can change his/her own password. Therefore you need to log in as root first. Enter the following command to do so:

@ sudo -i

The system will prompt you to enter the current sudo password. Please enter the password and hit Enter.

Now you will be logged in as root user; you can see that indication in the command prompt.

Step 3: Change the sudo password through the passwd command

Now that you are logged in as root, you can change the passwd for the current (root) user by using the passwd command as follows:

$ passwd

When you enter the passwd command, the system will prompt you to enter the new UNIX root password. When you enter the new password and hit enter, the system will prompt you to retype the new UNIX root password. After doing so, the system will confirm that the password is updated successfully.

Now whenever you need to log in as root or perform any installation and configuration operation that requires root authorization, you will be using this new password.

Step 4: Exit the root login and then the Terminal

When you are done with changing the password, you can log out of the root prompt by entering the following command.

$ exit

Once you are logged out, type the exit command again to exit the Terminal application.

An Alternative

A simple alternative is to enter the following command that lets you log in as root and enter the password-changing command for root, in a single command:

$ sudo passwd root

When you enter the above command, the system will prompt you to enter the new UNIX root password. When you enter the new password and hit enter, the system will prompt you to retype the new UNIX root password. After doing so, the system will confirm that the password is updated successfully.

With the help of this article, you can change the password for sudo and make your system secure from any malicious activity time and again.

How to Change sudo Password in Ubuntu 22.04

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8 Ways to Generate a Random Password on Linux Shell

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:09:00 +0000

A strong password is very important when you authenticate to a service with a username and password. Sometimes you need to protect your account or server and try to keep your data safe. It is often said that a strong password must have at least 14 characters, with variations such as lower and upper case letters and alphabets. Most of the time, a long password is considered much more secure than a short one because it is hard to get. In this tutorial, we will learn many ways to create a secure password using the Linux command line. We will look at many different ways you can create a stronger and more secure password using the Linux command line. If you want to create a strong password using the command line, there are several methods and utilities available to you. We will discuss many of these methods and you can choose one of the methods to create a password depending on your needs.

Generation of a password with OpenSSL

Several methods, exist in Linux to create and generate the passwords for the Linux command line. The first one we are trying is by using OpenSSL. Following are the steps that need to be followed for this purpose.

Step 1: First of all, open Terminal by clicking on the Ubuntu launcher and searching for Terminal.

Step 2: Now click on the Terminal and wait for the terminal to open.

Step 3: Once the terminal is opened, you will have a screen like this:

Step 4:

The command that is used to generate a stronger password includes the OpenSSL rand function. This will help us generate 14 random characters in a string. The command is:

openssl rand -base64 14

The outcome will be a strong password of 14 characters as shown below.

Generation of a password using urandom

The second command which we are using to generate a password has filtered /dev/urandom�output with�tr. This will allow us to delete all of the unwanted characters and then help us to print the first 14 characters only.

The output of the above command is as follows:

The output has allowed us to print the first 14 characters only by deleting all of the unwanted ones.

Generation of a password using pwgen

For using pwgen we need to install this tool first. This tool will help us generate some random yet meaningless passwords. Although the passwords generated by it are random still are pronounceable. So, we will now install the tool using the following command.

Enter the credentials as asked

The installation will eventually begin. The command line will look just like the screen below.

Once the installation has been done, we will generate a random string having 14 characters in it.

The string we got randomly is this one.

Generation of a password using gpg

Gpg can also be used to generate a strong password of 14 characters. The gpg tool uses the following command to generate the 14 characters.

The outcome of this command is

And in the end, we have a password generated which is.

Generation of a password using SHA

We will use SHA in this method, we can also hash the date. It runs through the base64. As a result, we get an output as the top of the 32 characters.

Here is the outcome containing the 32 characters yet a strong password to keep the system safe.

Generation of a password via an easy way

The generation of a password is quite easy using the command line. Although it is not random still it is useful if we utilize the whole password. The easiest command for this purpose is as follows:

The outcome of the above command is a string as shown below.

And this command is very easy, and simple enough to remember.

Generation of a password using apg

APG is an Automatic Password Generator, it is already installed on all Ubuntu systems. It is also an easily used utility. It helps us generate various passwords that are random input.

In order to generate entire random passwords, we can run�apg -a 1, which will give us the passwords with 8-10 random characters. The command we used for this purpose is apg �a 1. We will run and see various passwords generated in the output.

The output has many random passwords.

Generation of a password using makepasswd

�makepasswd� can also be used to generate passwords. For using this utility, we install it at first. We will use the command�sudo apt-get install makepasswd.

Enter the required credentials.

On writing the credentials, the installation will begin.

Press Y to continue

Once the utility has been installed, we will write the command which is makepasswd �count NumberOfPasswords �minchars MinLengthOfPassword.

At first, we tell how many passwords we are aiming to generate and what must be the length of each of the password. Here we have asked to generate 4 passwords with length as eight for each of it.

The outcome is shown below. We have a total of 4 passwords with 8 characters in each of them.

The command is responsible for generating a list of random passwords based on the number of passwords we want to generate and the length is also defined by us.

Conclusion

In this tutorial, we have discussed many ways to generate passwords from the Linux command line. There are many methods that already exist. Some of the utilities are already present in the Linux command line, while the others are easy to install with the available commands. In this tutorial, we have discussed the utilities openssh, urandom, pwegn, gpg, sha, date, apg and makepasswd. All of these commands guarantee the generation of a stronger password from the Linux command line and are useful for users to ensure the security of their systems.

8 Ways to Generate a Random Password on Linux Shell

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How to keep Rocky Linux 8 up to date

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:08:00 +0000

As a system administrator, it is your job to keep the system up to date with the latest packages to increase system stability and reduce security risks. If you haven�t configured your server to check for updates automatically, you�ll have to update them manually.

In this tutorial, we�ll learn how to keep Rocky Linux 8 Server up to date. So, let�s get started.

Manual Rocky Linux update using dnf

To check if there is any update available for your installed packages, navigate to the terminal and type the following command.

# sudo dnf check-update

If there is any update available, it will list down the updated available packages, update the single package, and use the following command.

# sudo dnf update httpd

To update the system development tools, use the following command.

# sudo dnf update "Development Tools"

To update all of your system packages at a time, execute the following command.

# sudo dnf update

It�s a good practice to keep your software packages updated with the latest version to minimize the security risk.

Automatic Rocky Linux updates with dnf

It�s a difficult task for a system admin to check system updates manually daily, when you have a large number of Infrastructure you won�t be able to check one by one. To set the system updates automatically, install the following package using the following command.

# sudo dnf install dnf-automatic

The Next step is to configure the automatic update, for this navigate to the dnf-automatic configuration file located at /etc/dnf/automatic.conf, and set the values for update.

# sudo vim /etc/dnf/automatic.conf

Set the download_updates and apply_updates parameters to YES, so every time the new updates come, it will install and notify through an email.

To set up an email notification, set the email_from and email_to parameters so it will notify you about the latest updates.

Conclusion

In this tutorial, we learned how to update a Rocky Linux 8 server with the latest software packages to reduce the security risk using automatically and manually.

How to keep Rocky Linux 8 up to date

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How to Install Postfix on AlmaLinux 8, CentOS 8 and Rocky Linux 8

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:07:00 +0000

Postfix is an efficient Mail Transfer Agent used for routing and sending receiving emails which is available as OpenSource software. It is the most well-known email server used in different Linux distributions. This is actually the replacement of an old Sendmail MTA that is pre-installed on the latest Rocky Linux versions as well. You may need to install the postfix mail server on your system. Today, we will explain the installation process of the postfix server on the Rocky Linux 8 system using the Terminal.

All commands will run on the terminal application in this article. To access the terminal, click on the Activities option located at the top left corner of Rocky Linux 8 environment, and then click on the Terminal from the left pane of your desktop.

Installation of Postfix on Rocky Linux 8

To install the Postfix on Rocky Linux 8, you need to follow the following steps:

Remove Sendmail

First, you need to remove the Sendmail from your system. Therefore, you can easily check that Sendmail is pre-installed on your system or not by using the following command:

$ rpm -qa | grep sendmail

If it is already installed, then you will see the installed version will display on the terminal. Otherwise, it will show any output on the screen. In this situation, you can leave this step.

You can remove the Sendmail by typing the following command on the terminal:

$ yum remove sendmail*

$ dnf remove sendmail

Update system

After removing the Sendmail, you will update your system by executing the following command:

$ dnf update

Install Postfix

Once you verify that there is no other MTA is running on your system then, you will install the postfix server by typing the following command:

$ sudo dnf install postfix

The confirmation prompt will interrupt the installation and ask for the confirmation to install the postfix server on the CentOS system. Press �y� in case of yes and then, hit �Enter� key to proceed with the further installation process.

Once the installation of the Postfix server is completed, you can verify that either it is now installed on your system or not by running the following command on the terminal:

$ rpm -qa|grep postfix

The following output should display on your system:

Enable Postfix Service

Now, the postfix server has been installed on your system. Enable and restart the Postfix services by running the below-mentioned commands:

$ systemctl enable postfix

After executing the above command, it will ask you to enter the login password for authentication. Enter the password and click on the �Authenticate� button. You will see the following output with symlink creation on the Terminal window:

Now, start the postfix services by running the following command:

Again, you need to authenticate the user. Enter the password and then hit on the �Authenticate� button.

After that run the following command to check the postfix services status:

$ systemctl status postfix

The following output will show on the Terminal window:

As you can see in the above image the Postfix services are running on this system.

Next, configure the postfix mail server to send emails to your local server. To exit from the current window press �Ctrl + c�.

Install Email Client mailx

Before start the configuration of the postfix server, you need to first install mailx email client on the system by typing the following command:

$ sudo dnf install mailx

Confirm the installation of the mailx package by pressing �y� and then hit �Enter�. Now the installation of mailx will be started and once completed, you will be notified as shown in the following screenshot.

Now, you can easily send emails to your local email server. For example, we are sending an email subject test mail to the recipient admin. For this purpose, we have typed the below-mentioned command on the Terminal:

$ mail kbuzdar

The term �mail� in the above command is referring to a client and the recipient is �kbuzdar� here. The �.� sign at the end of the emails sends the signal to the mail client that the email is ended now. Now, it will be sent to the postfix server for email delivery.

To check whether the email reached its destination or not, log in as the root user from the recipient side, and then write �mail� on the Terminal.

# mail

The following list of emails will display on the terminal including the last email that you have sent will show at the end.

Conclusion

That�s all about the Postfix server installation on Rocky Linux 8 using the command line. Moreover, you have seen how to send emails to the local server via the Postfix services. You can send emails to a particular domain by changing the name of your machine. I hope you liked this article and it may help you in the future.

How to Install Postfix on AlmaLinux 8, CentOS 8 and Rocky Linux 8

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How to Change the Keyboard Layout in Debian Desktop

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:06:00 +0000

The keyboard in Linux operating system comes in a variety of layouts for different languages. Even for a single language, there are several layouts. When using our systems, many of us like to use our native language as the main input language. The Debian operating system allows us to add any language as the primary input language and set it as the default language. It also allows us to add multiple keyboard layouts and switch between them whenever we want.

In this tutorial, we will explain step by step how you can change the keyboard layout in your Debian system to match your desired input language.

We have used GNOME Desktop on Debian to execute the commands and procedures mentioned in this article. This has been tested on Debian 10 and Debian 11.

Add Keyboard Layout language as Input Resource

We can change the keyboard layout from the Linux Settings utility. Settings utility can be opened via the following method:

Click the downward arrow at the top right corner of your Debian desktop. From the menu that appears, click the System settings icon as shown in the following screenshot.

Alternatively, you can open settings utility by searching it from the Application�s menu.

When the Settings window opens, go to the Region & Language tab. Then on the corresponding right pane, click the + button under Input Sources.

Then from the Add an Input Source dialog box, select the language you want to add as an input source and then click Add button.

Now your selected language will be shown under the Input Sources as a new keyboard layout.

Under the list of Input Sources, you will see the up and down arrows. Using these arrows, you can set any language as a default layout. The one at the top of the list will be used as a default and primary keyboard layout.

Switch between Keyboard Layouts

After adding a keyboard layout, you will now see the keyboard selection icon at the top right corner of the desktop. When you click the downward arrow in front of it, a drop-down menu will appear allowing you to select the keyboard layout.

An alternative and the quickest way to switch between the keyboard layouts is by using the keyboard shortcut that is Super key+ Space key. This is the default keyboard shortcut for switching between keyboard layouts. However, you can also change this shortcut from the keyboard settings.

In this article, you have learned how to change the keyboard layout in a Debian OS. Now you are able to choose and set your preferred input language for the default keyboard layout.

How to Change the Keyboard Layout in Debian Desktop

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How to Mount NFS on Debian 11

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:05:00 +0000

With NFS (Network File System), you can share files and folders with other systems in a network. NFS is based on a client-server architecture that allows users to remotely connect and access files through the network. With NFS, users can access shared files and folders as if they exist in their own system.

In this article, we will be discussing how to mount NFS on Debian 11 system. We will cover:

Mounting the NFS file system manually
Mounting the NFS file system automatically
Unmounting the NFS file system

We have used Debian 11 machine for explaining the commands and procedures mentioned in this article. More or less the same procedure can be followed in Ubuntu and older Debian distributions.

We will run the commands on Debian Terminal. To open the Terminal, hit the super key on your keyboard and search for it using the search bar that appears. From the results, click the Terminal application to open it.

If you do not have an NFS server yet, see here how to configure NFS server on Debian and NFS server on Ubuntu.

Prerequisites

For the client machine:

Debian 11 or Debian 10
User with sudo privileges

For the remote server:

NFS server is installed
NFS server shared directory is exported
NFS clients are allowed through the firewall

Once you have the above prerequisites completed, you can follow the below procedures in order to mount NFS on the client machine.

Install NFS Client Package on the client machine

You will need to install the NFS client package on the client machine in order to mount share directories on it. To install the NFS client package on the client computer, run the following commands in the Terminal:

$ sudo apt install nfs-common

After running the above command, the system might ask for confirmation if you want to continue the installation or not. Press y to continue, after that, the NFS client package will be installed on your system.

Step 1: Create a mount point for the shared directory of NFS server�s

You will need to create an empty directory for the mount points on the client machine. This empty directory will act as the mount point for the folders shared remotely.

Under the directory /mnt, we created a new mount folder �client_sharedfolder� using the below command:

$ sudo mkdir -p /mnt/client_ shareddirectory

Step 2: Mount the NFS server shared folder on the client

Use the following syntax to mount the shared NFS folder into the client�s mount point directory.

$ sudo mount [nfs_server]:/[nfs_shareddirectory] [client_mountpoint]

Where

[nfs_server] is the NFS server�s IP address which you can find by running the �$ ip a� command on the NFS server.
[nfs_ shareddirectory] is the shared folder on the NFS server
[client_mountpoint] is the mount point folder on the client�s machine

From the above screenshot, you can see that 192.168.72.144 is the IP address of the NFS server. The /mnt/sharedfolder is the shared folder on the NFS server and the /mnt/client_sharedfolder is the mount point folder on the client�s machine.

Once you have mounted the NFS server shared folder on the client machine, you can verify it. Issue the following command in Terminal to do so:

$ df -h

From the above screenshot, you can see the shared folder mounted on the client�s machine mount point.

Step 3: Verify NFS share

Once the NFS server share is mounted on the NFS client, try to access some files located on the server machine. Create any test file or directory on the NFS server computer, and try to access it from the client system.

In the NFS server machine, move inside the shared folder and create some files or folders.

Now in the client machine, issue the following command to check if these files exist:

$ ls /mnt/client_sharedfolder/

The method we have discussed above only mounts the file system temporarily on the client�s system. After you restart the system, the NFS file system will no longer remain mounted on the system.

Mount an NFS File System automatically

You also have the option to automatically mount the file system. It saves you from the hassle of mounting the file system manually every time the machine is restarted. For this purpose, you will need to edit the /etc/fstab file. Issue the following command in Terminal in order to do so:

$ sudo nano /etc/fstab

Then insert an entry in this file using the below syntax:

[nfs_server]: [nfs_shareddirectory] [client_mountpoint] nfs defaults 0 0

Where:

[nfs_server] is the NFS server�s IP address
[nfs_shareddirectory] is the shared folder on the NFS server
[client_mountpoint] is the mount point on the client�s machine
nfs is the file system type.

From the above screenshot, you can see that the 192.168.72.144 is the IP address of the NFS server, /mnt/sharedfolder is the shared folder on the NFS server and the /mnt/client_sharedfolder is the mount point on the client�s machine.

Once you have done with the above configurations, save, and close the /etc/fstab file. Now when you will restart the system, the NFS file system will be automatically mounted at the specified mount point.

Unmount the NFS File System

If you do not want the NFS file system to remain mounted anymore, you can unmount it from the client�s machine. To do so, issue the following command in Terminal:

$ sudo umount [mountpoint_name]

Replace the [mountpoint_name] by the actual name of your mount point folder.

Note: Mounting the NFS files system using the /etc/fstab file automatically mounts the file system to the specified mount point on the next restart even if you unmount it using the umount command.

Mounting the NFS file system on Linux is an easy task for storing and accessing the files through the network. In this article, you have learned about mounting and unmounting the NFS file system on the Debian 11 machine. I hope it will be helpful if you ever need to mount or mount the NFS file system on any Debian or Ubuntu machines.

How to Mount NFS on Debian 11

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How to Install Debian on Virtual Box

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:01:00 +0000

The document will show you the step-by-step installation process of Debian 10 on Virtual Box. Virtual box is greatly recommended for IT users, students, and even professionals who have to work on multiple operating systems at once. Instead of installing different operating systems on your machine according to work requirements which involve complex setup process, frequent restarting of PC, data overwriting, and infected disk space. Therefore it is highly recommended to have Virtual Box Software in your machines that enables to you create as many VMs as you want according to work/task specifications.

Debian 10 is Linux operating system distribution, which is free and open-source software. Also, Debian 10 has further extended versions of it.

Prerequisites for installing Debian on Virtual Box

For installing Debian 10, you need to complete the following prerequisites of the process:

Internet connectivity.
Installed Virtual Box version 6.1.12 on your machine.
At least 8GB of RAM on your machine.
At least 20GB of free disk space on your machine.

Installing Debian

For installing Debian 10 on Virtual Box version 6.1.12, you need to follow the following steps in order:

Step 01: Open the Oracle VM Virtual Box software

After opening the Virtual Box, go to the top left corner and click on the new button to create a new VM, as shown in the below image.

Step 02: Enter the VM name and the required version

Whenever you create a new VM, choose a relevant and significant name for it. Since this guide is for installing Debian 10 on Virtual Box 6.1.12, that is why I write Debian 10 in the name field, the user can choose or keep any name of his/her choice (look at the highlighted first column in the image attached below). Let�s suppose, if the user is creating the VM for Debian version 10.5, he/she can keep the name as Debian10.5 too, depending upon his/her choice.
As Debian 10 is Linux operating system distribution, make sure the �Type� is set automatically to Linux as you enter the VM name in the name field as highlighted in the third column in the below image.
In the version field, two versions are given for 32-bit and 64-bit operating systems. With the 32-bit version, the user will be able to set the RAM/Memory size for his VM limited to 4GB. Whereas, with the 64-bit version, the user can be able to set up 16 Exa-Bytes of RAM/Memory size for his VM. The user can choose anyone of both concerning his system specifications. In the particular case, I am going to choose the 64-bit in the version field as highlighted in the fourth column of the attached image.
Click Next.

Step 03: Set the memory size/RAM

For creating a virtual machine, the upper limit of memory size is 16384MB(16.384GB) and the lower limit is 4MB(0.004 GB). The user can select any memory size in this range keeping in mind his system specifications ( precisely his system RAM size).
For this particular guide, I am setting the memory size as 4096 MB.
After setting the memory size, click the Next button.

Step 04: Create hard disk for VM

Mark the second option: create virtual hard disk now and click the Create button, for creating a virtual hard disk for Debian 10.

Step 05: Set hard disk file type

Mark the first option VDI (VirtualBox Disk Image) and click the Next button. It will set the hard disk file type as VDI.

Step 06: Set the storage type for the hard disk

Mark the option named as fixed size and click the Next button.

Step 07: Select the file location and size for VM hard disk

To avoid the exhaustive file and data searching later. Keep the default file location, though you can change the file location as per your desire.
For creating a virtual machine, the upper limit of size for a virtual hard disk file is 20TB. and the lower limit is 4MB. The user can select any file size in this range keeping in mind the prerequisite for a particular installation i.e there should be at least 20GB of free disk space on his machine.
For this particular guide, I am setting the memory size as 20GB(20,000MB) according to free hard disk space on my system.
After setting the hard disk file size, click the Create button.

Clicking the create button, will start creating the fixed medium storage unit, as shown in the below image.

Step 08: Add the ISO file for Debian 10

Before moving ahead, first, you need to download Debian 10 ISO Image. You can download it from its official website https://cdimage.debian.org/debian-cd/current-live/amd64/iso-hybrid/. From this website, you can download ISO image with concern to your Desktop environment (cinnamon, gnome, KDE, and more). In this documentation, I will prefer cinnamon. Click on the link for downloading the ISO file for cinnamon as highlighted in the below image.

After creating the virtual hard disk for VM:

Go to the left corner.
Click the right button on the Debian10 field.
Click the settings button.

After going into the settings:

Click the Storage on the left side.
Select Empty under the Storage Devices field.

Storage Devices �> Controller: IDE �> Empty

Click on the CD/DVD icon and select Choose/Create a Virtual Optical Disk.
Click Ok.

Clicking the Ok button will show a Dialogue box. Follow the following bullets highlighted in the below-attached images as well:

Click on the Add button.

Select the Debian 10 ISO file from your downloads and click on the Open button.

Select the ISO file for Debian 10 and click on the Choose button.

Performing the above steps, it will add the Debian 10 ISO file under the storage devices. This is shown highlighted in the below image.

Step 09: Installing the new VM

Once you have done with all of the above-mentioned steps, you can now install the new VM. For doing so, follow the following bullet points:

Click on the Start button as shown highlighted in the below image.

Click on the first option of the Main Menu.

It will take you to the following screen:

Click on the install Debian button.

Set American English as your default installation language and click the Next button.

Select your current location and click on the Next button.

Select the keyboard layout of your choice and click the Next button.

Tick mark the �erase disk� option and click the Next button.

Step 10: Setting up User Account

After getting done with the above steps, it will now take you to the next tab named Users for setting your account. Look at the highlighted parts of the attached image below for setting up the account.

Set username.
Set password.
Confirm password.
Click on the Next button.

The next tab named �Summary� will give an overall preview of all your selected fields and choices, along with the options of Back, Install and Cancel in the bottom right corner.

Click on the Install button.

After clicking on the install, the installation process will begin and usually takes some time.

Once it has done, it will take you to the last tab named Finish and you will be required to restart your VM. Tick the Restart Now and then click the Done button as highlighted in the below image and your VM will be restarted. You can now able to work on your new VM.

Conclusion

This document will guide the professional as well as na�ve users through the whole step by step process for an easy and steady way of installing Debian on Virtual Box version, showing everything highlighted in the attached images for your convenience.

How to Install Debian on Virtual Box

How to Restart Network on Ubuntu 22.04

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 15:00:00 +0000

Whenever a problem occurs with the system, the main solution is to perform a restart or reboot the system. Similarly, if a problem occurs with the network, then its easy treatment is to restart the network. There are many scenarios where you may need to restart the network on Ubuntu like settings of the network were changed or the active network connection not working properly. Restarting the network services is equally important for all Linux systems.

In this article, we will check how to restart the network on Ubuntu 22.04 and Ubuntu 20.04 systems.

Using the following different methods, you can restart the network on Ubuntu.

Restart network using GUI
Restart network using the command line

Depending on your ease, you can choose one that suits you.

Prerequisites

We are assuming that you are using the Gnome desktop on your Linux system. You should be logged in as a root user or you have sudo privileges to run all commands.

Method 1: Restart Network using GUI

When you restart the network using the GUI, then you can follow the following two different options.

Restart Network from the Desktop

In this method, you can restart the network from the Desktop. To do that, right-click on the top right corner on the network icon, and the following drop-down list will display on the right corner:

Click on the �wired connected� option from the list and select �Turn off� that will disable the network connection.

Now, follow the above-mentioned process and again enable the network by clicking the connect option as follows:

The network connection has been re-establish now.

Network Restart using Gnome Settings

Click on the arrow sign located at the top right corner and then choose �Settings�.

You can also go into the Settings by using the application search bar as follows:

You will see the following window on the desktop. Select the �network� option from the left sidebar and here you can enable or disable the connected network connection.

Method 2: Restart network using the command line

Using this method, you can restart the network using the following different ways:

Restart Network using the service manager

The most simple and easiest way to restart the network using the network service manager. Launch the terminal and type the following command on it:

$ sudo service network-manager restart

Verify

Use Systemd to Restart Network

Systemd has an array of system components that can also handle network services. Restart network service using systemd, directly restart the network services instead of going through any other hoops.

$ sudo systemctl restart NetworkManager.service

verify

Restart Network through the Nmcli

Nmcli is the most commonly used tool for managing network connections. You can turn off the connect using the following command:

$ sudo nmcli networking off

Use the command below to turn on the network connection.

$ sudo nmcli networking on

Verify

Using ifdown and ifup commands Restart Network

The ifdown and ifup commands are used to handle the different network interfaces on Linux.

These two packages are not preinstalled on Ubuntu. Therefore, you need to install these packages by using the following command:

$ sudo apt update && sudo apt install ifupdown -y

To turn off the network, use the ifdown and turn it on by using the ifup command as follows:

$ sudo ifdown -a && sudo ifup -a

Restart Network using the nmtui

Nmtui is another tool for managing network connections and provides an interactive environment. This tool comes pre-installed by default on Ubuntu. Therefore, just launch it using the following command:

$ sudo nmtui

The following interface will display on the terminal:

Choose �Activate a connection� using the downward arrow key and then hit �Enter�.Now, deactivate this connection by selecting the �deactivate� option and hitting �Enter�.

Once the connection is deactivated, again �Activate� this connection as follows:

Once the network is restarted, quit this application as follows:

Restart network using the IP command

The IP command is one more alternative that you can use in managing the network connections on Linux.

First, you will find your target network interface by using the following command:

$ ip link show

Here, enp0s3 is our target network. Start the network by typing the following command:

$ sudo ip link set enp0s3 down

$ sudo ip link set enp0s3 up

Conclusion

Restarting the network is a good solution for solving a network problem. If you still have the same problem then you can also reboot or restart your system. From the above all mentioned ways, I hope you have learned a lot.� But, in case of any issue, you can send us your feedback.

How to Restart Network on Ubuntu 22.04

How to install PHP 5.6, PHP 8.0 and PHP 8.1 on Ubuntu 22.04 LTS

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 14:57:00 +0000

PHP is a recursive acronym for Hypertext Processor. It is an open-source general-purpose scripting language that is widely used in web development because of its ability to be embedded in HTML. A scripting language is used to write pre-written programs that are later used to automate tasks. PHP scripts are commonly used on Linux, Unix, Windows, Mac OS, and other operating systems. When using PHP in web development, you are free to choose your web server and the underlying operating system.

This article describes step-by-step how to install PHP versions 5.6, 8.0, and 8.1 on your Ubuntu. After installing the two versions, it also explains how you can disable one version and enable another version as the default version for the system.

We have run the commands and procedures mentioned in this article on an Ubuntu 22.04 LTS system. The same commands will work on the old Ubuntu 20.04 LTS version as well.

In this article, we use the Ubuntu command line, the terminal, to install and configure PHP. You can open the Terminal application using either the System Dash or the Ctrl+Alt+t key combination.

The official PHP website, php.net, provides a list of all PHP versions to date at the following link:

http://php.net/releases/

From this list, you can choose whichever version you wish to install on your system. The list includes downloadable tar.gz packages but in this article, we will describe installing PHP through the Ondrej PPA repository.

Install PHP version 5.6

In order to install PHP version 5.6, first, open your Ubuntu Terminal and enter the following command in order to add the Ondrej PHP repository to your Ubuntu.

$ sudo add-apt-repository ppa:ondrej/php

This repository contains all the released versions of PHP to date.

Once the Ondrej repository is added, you need to update your system�s repository index with that on the Internet. This way you can install the latest available version of software on your system. Enter the following command in order to do so:

$ sudo apt update

Now install any pending updates with the following command:

$ sudo apt upgrade

Now is the time to install PHP 5.6 on your system. Enter the following command as sudo as only an authorized person can install/uninstall and configure software on Ubuntu:

$ sudo apt install -y php5.6

The software will then be installed on your system.

In order to check the version number of your installed PHP, run the following command:

$ php -v

or,

$ php --version

The command will also verify that PHP is now indeed installed on your system.

Now you have PHP 5.6 installed, but most use cases require that you install additional PHP modules like MySQL support, Curl, GD, etc. Run the below command to install some commonly used modules.

apt-get install php5.6-gd php5.6-mysql php5.6-imap php5.6-curl php5.6-intl php5.6-pspell php5.6-recode php5.6-sqlite3 php5.6-tidy php5.6-xmlrpc php5.6-xsl php5.6-zip php5.6-mbstring php5.6-soap php5.6-opcache libicu65 php5.6-common php5.6-json php5.6-readline php5.6-xml

Install PHP version 8.0

In order to install PHP version 8.0, first, open your Ubuntu Terminal and enter the following command in order to add the Ondrej PHP repository to your Ubuntu system (in case you have not done that already in the above chapter to install PHP 5.6).

$ sudo add-apt-repository ppa:ondrej/php

This repository contains all the released versions of PHP till date.

Once the Ondrej repository is added, you need to update your system�s repository with that on the internet. This way you can install the latest available version of a software on your system. Enter the following command in order to do so:

$ sudo apt update

Now is the time to install PHP 8.0 to your system. Enter the following command as sudo as only an authorized person can install/uninstall and configure software on Ubuntu:

$ sudo apt install -y php8.0

The software will then be installed on your system.

In order to check the version number of your installed PHP, run the following command:

$ php -v

or,

$ php --version

The command will also verify that PHP is now indeed installed on your system.

Now you have PHP 5.6 installed, but most use cases require that you install additional PHP modules like MySQL support, Curl, GD, SQLite, XML, etc. Run the below command to install some commonly used modules.

apt install php8.0-gd php8.0-mysql php8.0-imap php8.0-curl php8.0-intl php8.0-pspell php8.0-sqlite3 php8.0-tidy php8.0-xsl php8.0-zip php8.0-mbstring php8.0-soap php8.0-opcache libonig5 php8.0-common php8.0-readline php8.0-xml

Install PHP version 8.1

In order to install PHP version 8.1, first, open your Ubuntu Terminal and enter the following command in order to add the Ondrej PHP repository to your Ubuntu system (in case you have not done that already in one of the above chapters).

$ sudo add-apt-repository ppa:ondrej/php

This repository contains all the released versions of PHP to date.

$ sudo apt update

Now is the time to install PHP 8.1 on your system. Enter the following command as sudo as only an authorized person can install/uninstall and configure software on Ubuntu:

$ sudo apt install -y php8.1

The software will then be installed on your system.

In order to check the version number of your installed PHP, run the following command:

$ php -v

or,

$ php --version

The command will also verify that PHP is now indeed installed on your system.

Now you have PHP 8.1 installed, but most use cases require that you install additional PHP modules like MySQL support, Curl, GD, SQLite, XML, etc. Run the below command to install some commonly used modules.

apt install php8.1-gd php8.1-mysql php8.1-imap php8.1-curl php8.1-intl php8.1-pspell php8.1-sqlite3 php8.1-tidy php8.1-xsl php8.1-zip php8.1-mbstring php8.1-soap php8.1-opcache libonig5 php8.1-common php8.1-readline php8.1-xml

Switching between installed PHP versions

If you have two or more versions of PHP installed on your system, you can configure your system to use one of them as the default PHP version. For this, it is first important to learn which version is currently enabled as default on your Ubuntu system.

Check which version is enabled

We will describe two ways to check which PHP version is enabled on your system; one is through Apache2 and the other is through the CLI.

Through Apache2

Change the current directory to /etc/apache2 as follows:

$ cd /etc/apache2

In the apache2 directory, run the following command to list all the available modes of PHP on your system and know which one of them is currently enabled:

$ ls -l mods-*/*php*

In the output, you can see that the currently enabled version of PHP is highlighted. In our case, it is PHP 5.6.

Through CLI

It is also very simple to check the currently enabled version of PHP through the CLI. Run the following command which is used to update the default alternative to a software on Ubuntu and thus lists all the available alternatives.

$ sudo update-alternatives --config php

In the output of the above command, the currently enabled version of PHP is indicated by a * symbol. You can see that in our case, it is PHP 5.6.

Switch from PHP 5.6 to PHP 8.0 or PHP 8.1

We will describe two ways to switch from PHP 5.6 to PHP 8.0; one is through Apache2 and the other is through the CLI.

Through Apache2

First, disable the currently enabled version of PHP through the following command:

$ sudo a2dismod php5.6

And then, enable the other version of PHP through the following command:

$ sudo a2enmod php8.0

�

If you want to switch to PHP 8.1 instead, use this command:

$ sudo a2enmod php8.1

Now when you restart the apache2 service through the following command, PHP 8.0 will be enabled on your system.

$ sudo service apache2 restart

Through CLI

Use the following command to update your system to now use PHP 8.1 as the default PHP version.

$ sudo update-alternatives --set php /usr/bin/php8.1

Alternatively, you can use the following command to achieve the same purpose:

$ sudo update-alternatives --config php

The command lists all the available versions of PHP installed on your system. Enter the selection number of the version you want to enable on your system and hit enter. For example, if I enter 2, PHP 5.6 will be enabled on my system.

Switch from PHP 8.0 to PHP 5.6

We will describe two ways to switch from PHP 8.0 to PHP 5.6; one is through Apache2 and the other is through the CLI.

Through Apache2

First, disable the currently enabled version of PHP through the following command:

$ sudo a2dismod php8.0

And then, enable the other version of PHP through the following command:

$ sudo a2enmod php5.6

Now when you restart the apache2 service through the following command, PHP 5.6 will be enabled on your system.

$ sudo service apache2 restart

Through CLI

Use the following command to update your system to now use PHP 5.6 as the default PHP version.

$ sudo update-alternatives --set php /usr/bin/php5.6

Alternatively, you can use the following command to achieve the same purpose:

$ sudo update-alternatives --config php

The command lists all the available versions of PHP installed on your system. Enter the selection number of the version you want to enable on your system and hit enter so that the new version will be enabled.

This article will guide you in installing your desired version of PHP on Ubuntu 22.04. If you have more than one version of PHP installed on your system, the article also helps you in checking which version is currently enabled and also how to switch from one version to the other.

How to install PHP 5.6, PHP 8.0 and PHP 8.1 on Ubuntu 22.04 LTS

How to Install Fish Shell on Ubuntu and Linux Mint

noreply@blogger.com (Nick) — Wed, 02 Nov 2022 14:56:00 +0000

The Fish shell also known as the Friendly Interactive Shell is one of the richest Linux shells in terms of user experience. It comes with a whole bundle of useful features with the help of which users can use the command line interface very easily and conveniently. In this article, we will show you how to install Fish Shell on Ubuntu and Linux Mint.

Installation Procedure of the Fish Shell

To install the Fish shell on a Linux Mint 20 system, you will have to take a look at the following installation procedure. The first four steps of this method are related to the Fish shell installation whereas the last two steps are about its usage. You can also skip the last two steps if you want.

Step # 1: Adding the Fish Shell PPA Repository to Linux Mint 20

First, you need to add the Fish shell PPA repository to your system by running the command shown below:

$ sudo apt-add-repository ppa:fish-shell/release-3

Step # 2: Updating the System

Now, since we have added a new repository to our system, therefore, before proceeding any further, we will first update our system with the following command:

$ sudo apt-get update

Step # 3: Installing the Fish Shell on Linux Mint 20

After doing that, you can install the Fish shell on your system with the command stated below:

$ sudo apt-get install fish

Step # 4: Confirming the Fish Shell Installation

The Fish shell will install on your system after a few minutes of executing the installation command. However, if you want to confirm this installation, then you can check its version with the following command:

$ fish --version

You can see the version of the Fish shell in the image shown below:

Step # 5: Using the Fish Shell on Linux Mint 20: (Optional)

If you want to use the Fish shell after installing it, then you will have to run the following command:

$ fish

The Fish shell is shown in the image below:

The best thing about the Fish shell is that as soon as you will start typing a command in this shell to run it, you will see useful suggestions that you can choose to auto-complete your command. You can see the following image to understand this. We just typed an �s� and the Fish shell suggested a relevant command that we can choose:

Now, to select a command from the provided suggestions, you can simply press the �Tab� key and you will see a whole list of suggested commands you can simply choose one of them as shown in the image below:

Step # 6: Exiting from the Fish Shell in Linux Mint 20: (Optional)

If you want to exist from the Fish shell and return to your Bash shell, then you simply need to execute the following command:

> bash

Removal Procedure of the Fish Shell from Linux Mint 20:

For removing the Fish shell from Linux Mint 20, you need to perform the two steps mentioned below:

Step # 1: Remove Fish Shell from your System:

First, you need to completely remove the Fish shell from your system with the following command:

$ sudo apt-get purge --autoremove fish

Step # 2: Remove the Fish Shell PPA Repository from your System:

After removing the Fish shell completely from your system, you also need to remove its official PPA repository from your system that you have added previously. You can do this by running the command shown below:

$ sudo apt-add-repository --remove ppa:fish-shell/release-3

Conclusion

This article guided you on the installation of the Fish shell on a Linux Mint 20 system. Apart from that, it also enlightened you a little bit on the usage of this shell. Finally, it concluded with the removal procedure of the Fish shell from your system.

Tutorial: Web Scraping with Python Using Beautiful Soup

noreply@blogger.com (Nick) — Tue, 01 Nov 2022 15:31:00 +0000

March 30, 2021

Tutorial: Web Scraping with Python Using Beautiful Soup

Learn how to scrape the web with Python!

The internet is an absolutely massive source of data — data that we can access using web scraping and Python!

In fact, web scraping is often the only way we can access data. There is a lot of information out there that isn’t available in convenient CSV exports or easy-to-connect APIs. And websites themselves are often valuable sources of data — consider, for example, the kinds of analysis you could do if you could download every post on a web forum.

To access those sorts of on-page datasets, we’ll have to use web scraping.

Don’t worry if you’re still a total beginner!

In this tutorial we’re going to cover how to do web scraping with Python from scratch, starting with some answers to frequently-asked questions.

Then, we’ll work through an actual web scraping project, focusing on weather data.

We’ll work together to scrape weather data from the web to support a weather app.

But before we start writing any Python, we’ve got to cover the basics! If you’re already familiar with the concept of web scraping, feel free to scroll past these questions and jump right into the tutorial!

The Fundamentals of Web Scraping:

What is Web Scraping in Python?

Some websites offer data sets that are downloadable in CSV format, or accessible via an Application Programming Interface (API). But many websites with useful data don’t offer these convenient options.

Consider, for example, the National Weather Service’s website. It contains up-to-date weather forecasts for every location in the US, but that weather data isn’t accessible as a CSV or via API. It has to be viewed on the NWS site:

If we wanted to analyze this data, or download it for use in some other app, we wouldn’t want to painstakingly copy-paste everything. Web scraping is a technique that lets us use programming to do the heavy lifting. We’ll write some code that looks at the NWS site, grabs just the data we want to work with, and outputs it in the format we need.

In this tutorial, we’ll show you how to perform web scraping using Python 3 and the Beautiful Soup library. We’ll be scraping weather forecasts from the National Weather Service, and then analyzing them using the Pandas library.

But to be clear, lots of programming languages can be used to scrape the web! We also teach web scraping in R, for example. For this tutorial, though, we’ll be sticking with Python.

How Does Web Scraping Work?

When we scrape the web, we write code that sends a request to the server that’s hosting the page we specified. The server will return the source code — HTML, mostly — for the page (or pages) we requested.

So far, we’re essentially doing the same thing a web browser does — sending a server request with a specific URL and asking the server to return the code for that page.

But unlike a web browser, our web scraping code won’t interpret the page’s source code and display the page visually. Instead, we’ll write some custom code that filters through the page’s source code looking for specific elements we’ve specified, and extracting whatever content we’ve instructed it to extract.

For example, if we wanted to get all of the data from inside a table that was displayed on a web page, our code would be written to go through these steps in sequence:

Request the content (source code) of a specific URL from the server
Download the content that is returned
Identify the elements of the page that are part of the table we want
Extract and (if necessary) reformat those elements into a dataset we can analyze or use in whatever way we require.

If that all sounds very complicated, don’t worry! Python and Beautiful Soup have built-in features designed to make this relatively straightforward.

One thing that’s important to note: from a server’s perspective, requesting a page via web scraping is the same as loading it in a web browser. When we use code to submit these requests, we might be “loading” pages much faster than a regular user, and thus quickly eating up the website owner’s server resources.

Why Use Python for Web Scraping?

As previously mentioned, it’s possible to do web scraping with many programming languages.

However, one of the most popular approaches is to use Python and the Beautiful Soup library, as we’ll do in this tutorial.

Learning to do this with Python will mean that there are lots of tutorials, how-to videos, and bits of example code out there to help you deepen your knowledge once you’ve mastered the Beautiful Soup basics.

Is Web Scraping Legal?

Unfortunately, there’s not a cut-and-dry answer here. Some websites explicitly allow web scraping. Others explicitly forbid it. Many websites don’t offer any clear guidance one way or the other.

Before scraping any website, we should look for a terms and conditions page to see if there are explicit rules about scraping. If there are, we should follow them. If there are not, then it becomes more of a judgement call.

Remember, though, that web scraping consumes server resources for the host website. If we’re just scraping one page once, that isn’t going to cause a problem. But if our code is scraping 1,000 pages once every ten minutes, that could quickly get expensive for the website owner.

Thus, in addition to following any and all explicit rules about web scraping posted on the site, it’s also a good idea to follow these best practices:

Web Scraping Best Practices:

Never scrape more frequently than you need to.
Consider caching the content you scrape so that it’s only downloaded once.
Build pauses into your code using functions like time.sleep() to keep from overwhelming servers with too many requests too quickly.

In our case for this tutorial, the NWS’s data is public domain and its terms do not forbid web scraping, so we’re in the clear to proceed.

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The Components of a Web Page

Before we start writing code, we need to understand a little bit about the structure of a web page. We’ll use the site’s structure to write code that gets us the data we want to scrape, so understanding that structure is an important first step for any web scraping project.
When we visit a web page, our web browser makes a request to a web server. This request is called a GET request, since we’re getting files from the server. The server then sends back files that tell our browser how to render the page for us. These files will typically include:

HTML — the main content of the page.
CSS — used to add styling to make the page look nicer.
JS — Javascript files add interactivity to web pages.
Images — image formats, such as JPG and PNG, allow web pages to show pictures.

After our browser receives all the files, it renders the page and displays it to us.

There’s a lot that happens behind the scenes to render a page nicely, but we don’t need to worry about most of it when we’re web scraping. When we perform web scraping, we’re interested in the main content of the web page, so we look primarily at the HTML.

HTML

HyperText Markup Language (HTML) is the language that web pages are created in. HTML isn’t a programming language, like Python, though. It’s a markup language that tells a browser how to display content.

HTML has many functions that are similar to what you might find in a word processor like Microsoft Word — it can make text bold, create paragraphs, and so on.

If you’re already familiar with HTML, feel free to jump to the next section of this tutorial. Otherwise, let’s take a quick tour through HTML so we know enough to scrape effectively.

HTML consists of elements called tags. The most basic tag is the <html> tag. This tag tells the web browser that everything inside of it is HTML. We can make a simple HTML document just using this tag:

<html>

</html>

We haven’t added any content to our page yet, so if we viewed our HTML document in a web browser, we wouldn’t see anything:

Right inside an html tag, we can put two other tags: the head tag, and the body tag.

The main content of the web page goes into the body tag. The head tag contains data about the title of the page, and other information that generally isn’t useful in web scraping:

<html>

<head>

</head>

<body>

</body>

</html>

We still haven’t added any content to our page (that goes inside the body tag), so if we open this HTML file in a browser, we still won’t see anything:

You may have noticed above that we put the head and body tags inside the html tag. In HTML, tags are nested, and can go inside other tags.

We’ll now add our first content to the page, inside a p tag. The p tag defines a paragraph, and any text inside the tag is shown as a separate paragraph:

<html>

<head>

</head>

<body>

<p>

Here's a paragraph of text!

</p>

<p>

Here's a second paragraph of text!

</p>

</body>

</html>

Rendered in a browser, that HTML file will look like this:

Here’s a paragraph of text!

Here’s a second paragraph of text!

Tags have commonly used names that depend on their position in relation to other tags:

child — a child is a tag inside another tag. So the two p tags above are both children of the body tag.
parent — a parent is the tag another tag is inside. Above, the html tag is the parent of the body tag.
sibiling — a sibiling is a tag that is nested inside the same parent as another tag. For example, head and body are siblings, since they’re both inside html. Both p tags are siblings, since they’re both inside body.

We can also add properties to HTML tags that change their behavior. Below, we’ll add some extra text and hyperlinks using the a tag.

<html>

<head>

</head>

<body>

<p>

Here's a paragraph of text!

<a href="https://www.dataquest.io">Learn Data Science Online</a>

</p>

<p>

Here's a second paragraph of text!

<a href="https://www.python.org">Python</a> </p>

</body></html>

Here’s how this will look:

Here’s a paragraph of text! Learn Data Science Online

Here’s a second paragraph of text! Python

In the above example, we added two a tags. a tags are links, and tell the browser to render a link to another web page. The href property of the tag determines where the link goes.

a and p are extremely common html tags. Here are a few others:

div — indicates a division, or area, of the page.
b — bolds any text inside.
i — italicizes any text inside.
table — creates a table.
form — creates an input form.

For a full list of tags, look here.

Before we move into actual web scraping, let’s learn about the class and id properties. These special properties give HTML elements names, and make them easier to interact with when we’re scraping.

One element can have multiple classes, and a class can be shared between elements. Each element can only have one id, and an id can only be used once on a page. Classes and ids are optional, and not all elements will have them.

We can add classes and ids to our example:

<html>

<head>

</head>

<body>

<p class="bold-paragraph">

Here's a paragraph of text!

<a href="https://www.dataquest.io" id="learn-link">Learn Data Science Online</a>

</p>

<p class="bold-paragraph extra-large">

Here's a second paragraph of text!

<a href="https://www.python.org" class="extra-large">Python</a>

</p>

</body>

</html>

Here’s how this will look:

Here’s a paragraph of text! Learn Data Science Online

Here’s a second paragraph of text! Python

As you can see, adding classes and ids doesn’t change how the tags are rendered at all.

The requests library

Now that we understand the structure of a web page, it’s time to get into the fun part: scraping the content we want!
The first thing we’ll need to do to scrape a web page is to download the page. We can download pages using the Python requests library.

The requests library will make a GET request to a web server, which will download the HTML contents of a given web page for us. There are several different types of requests we can make using requests, of which GET is just one. If you want to learn more, check out our API tutorial.

Let’s try downloading a simple sample website, https://dataquestio.github.io/web-scraping-pages/simple.html.

We’ll need to first import the requests library, and then download the page using the requests.get method:

import requests

page = requests.get("https://dataquestio.github.io/web-scraping-pages/simple.html")

page

<Response [200]>

After running our request, we get a Response object. This object has a status_code property, which indicates if the page was downloaded successfully:

page.status_code

A status_code of 200 means that the page downloaded successfully. We won’t fully dive into status codes here, but a status code starting with a 2 generally indicates success, and a code starting with a 4 or a 5 indicates an error.

We can print out the HTML content of the page using the content property:

page.content

<!DOCTYPE html>

<html>

<head>

<title>A simple example page</title>

</head>

<body>

<p>Here is some simple content for this page.</p>

</body>

</html>

Parsing a page with BeautifulSoup

As you can see above, we now have downloaded an HTML document.

We can use the BeautifulSoup library to parse this document, and extract the text from the p tag.

We first have to import the library, and create an instance of the BeautifulSoup class to parse our document:

from bs4 import BeautifulSoup

soup = BeautifulSoup(page.content, 'html.parser')

We can now print out the HTML content of the page, formatted nicely, using the prettify method on the BeautifulSoup object.

print(soup.prettify())

<!DOCTYPE html>

<html>

    <head>

        <title>A simple example page</title>

    </head>

    <body>

        <p>Here is some simple content for this page.</p>

    </body>

</html>

This step isn’t strictly necessary, and we won’t always bother with it, but it can be helpful to look at prettified HTML to make the structure of the and where tags are nested easier to see.
As all the tags are nested, we can move through the structure one level at a time. We can first select all the elements at the top level of the page using the children property of soup.

Note that children returns a list generator, so we need to call the list function on it:

list(soup.children)

['html', 'n', <html> <head> <title>A simple example page</title> </head> <body> <p>Here is some simple content for this page.</p> </body> </html>]

The above tells us that there are two tags at the top level of the page — the initial <!DOCTYPE html> tag, and the <html> tag. There is a newline character (n) in the list as well. Let’s see what the type of each element in the list is:

[type(item) for item in list(soup.children)]

[bs4.element.Doctype, bs4.element.NavigableString, bs4.element.Tag]

As we can see, all of the items are BeautifulSoup objects:

The first is a Doctype object, which contains information about the type of the document.
The second is a NavigableString, which represents text found in the HTML document.
The final item is a Tag object, which contains other nested tags.

The most important object type, and the one we’ll deal with most often, is the Tag object.

The Tag object allows us to navigate through an HTML document, and extract other tags and text. You can learn more about the various BeautifulSoup objects here.

We can now select the html tag and its children by taking the third item in the list:

html = list(soup.children)[2]

Each item in the list returned by the children property is also a BeautifulSoup object, so we can also call the children method on html.

Now, we can find the children inside the html tag:

list(html.children)

['n', <head> <title>A simple example page</title> </head>, 'n', <body> <p>Here is some simple content for this page.</p> </body>, 'n']

As we can see above, there are two tags here, head, and body. We want to extract the text inside the p tag, so we’ll dive into the body:

body = list(html.children)[3]

Now, we can get the p tag by finding the children of the body tag:

list(body.children)

['n', <p>Here is some simple content for this page.</p>, 'n']

We can now isolate the p tag:

p = list(body.children)[1]

Once we’ve isolated the tag, we can use the get_text method to extract all of the text inside the tag:

p.get_text()

'Here is some simple content for this page.'

Finding all instances of a tag at once

What we did above was useful for figuring out how to navigate a page, but it took a lot of commands to do something fairly simple.

If we want to extract a single tag, we can instead use the find_all method, which will find all the instances of a tag on a page.

soup = BeautifulSoup(page.content, 'html.parser')

soup.find_all('p')

[<p>Here is some simple content for this page.</p>]

Note that find_all returns a list, so we’ll have to loop through, or use list indexing, it to extract text:

soup.find_all('p')[0].get_text()

'Here is some simple content for this page.'

f you instead only want to find the first instance of a tag, you can use the find method, which will return a single BeautifulSoup object:

soup.find('p')

<p>Here is some simple content for this page.</p>

Searching for tags by class and id

We introduced classes and ids earlier, but it probably wasn’t clear why they were useful.

Classes and ids are used by CSS to determine which HTML elements to apply certain styles to. But when we’re scraping, we can also use them to specify the elements we want to scrape.

To illustrate this principle, we’ll work with the following page:

<html>

    <head>

        <title>A simple example page</title>

    </head>

    <body>

        <div>

            <p class="inner-text first-item" id="first">

                First paragraph.

            </p>

            <p class="inner-text">

                Second paragraph.

            </p>

        </div>

            <p class="outer-text first-item" id="second">

                <b>

                First outer paragraph.

                </b>

            </p>

            <p class="outer-text">

                <b>

                Second outer paragraph.

                </b>

            </p>

    </body>

</html>

We can access the above document at the URL https://dataquestio.github.io/web-scraping-pages/ids_and_classes.html.

Let’s first download the page and create a BeautifulSoup object:

page = requests.get("https://dataquestio.github.io/web-scraping-pages/ids_and_classes.html")

soup = BeautifulSoup(page.content, 'html.parser')

soup

<html>

<head>

<title>A simple example page

</title>

</head>

<body>

<div>

<p class="inner-text first-item" id="first">

First paragraph.

</p><p class="inner-text">

Second paragraph.

</p></div>

<p class="outer-text first-item" id="second"><b>

First outer paragraph.

</b></p><p class="outer-text"><b>

Second outer paragraph.

</b>

</p>

</body>

</html>

Now, we can use the find_all method to search for items by class or by id. In the below example, we’ll search for any p tag that has the class outer-text:

soup.find_all('p', class_='outer-text')

[<p class="outer-text first-item" id="second"> <b> First outer paragraph. </b> </p>, <p class="outer-text"> <b> Second outer paragraph. </b> </p>]

In the below example, we’ll look for any tag that has the class outer-text:

soup.find_all(class_="outer-text")

<p class="outer-text first-item" id="second">

<b>

First outer paragraph.

</b>

</p>, <p class="outer-text">

<b>

Second outer paragraph.

</b>

</p>]

We can also search for elements by id:

soup.find_all(id="first")

[<p class="inner-text first-item" id="first">

First paragraph.

</p>]

Using CSS Selectors

We can also search for items using CSS selectors. These selectors are how the CSS language allows developers to specify HTML tags to style. Here are some examples:

p a — finds all a tags inside of a p tag.
body p a — finds all a tags inside of a p tag inside of a body tag.
html body — finds all body tags inside of an html tag.
p.outer-text — finds all p tags with a class of outer-text.
p#first — finds all p tags with an id of first.
body p.outer-text — finds any p tags with a class of outer-text inside of a body tag.

You can learn more about CSS selectors here.

BeautifulSoup objects support searching a page via CSS selectors using the select method. We can use CSS selectors to find all the p tags in our page that are inside of a div like this:

soup.select("div p")

[<p class="inner-text first-item" id="first">

First paragraph.

</p>, <p class="inner-text">

Second paragraph.

</p>]

Note that the select method above returns a list of BeautifulSoup objects, just like find and find_all.

Downloading weather data

We now know enough to proceed with extracting information about the local weather from the National Weather Service website!

The first step is to find the page we want to scrape. We’ll extract weather information about downtown San Francisco from this page.

Specifically, let’s extract data about the extended forecast.

As we can see from the image, the page has information about the extended forecast for the next week, including time of day, temperature, and a brief description of the conditions.

Exploring page structure with Chrome DevTools

The first thing we’ll need to do is inspect the page using Chrome Devtools. If you’re using another browser, Firefox and Safari have equivalents.

You can start the developer tools in Chrome by clicking View -> Developer -> Developer Tools. You should end up with a panel at the bottom of the browser like what you see below. Make sure the Elements panel is highlighted:

Chrome Developer Tools

The elements panel will show you all the HTML tags on the page, and let you navigate through them. It’s a really handy feature!

By right clicking on the page near where it says “Extended Forecast”, then clicking “Inspect”, we’ll open up the tag that contains the text “Extended Forecast” in the elements panel:

The extended forecast text

We can then scroll up in the elements panel to find the “outermost” element that contains all of the text that corresponds to the extended forecasts. In this case, it’s a div tag with the id seven-day-forecast:

The div that contains the extended forecast items.

If we click around on the console, and explore the div, we’ll discover that each forecast item (like “Tonight”, “Thursday”, and “Thursday Night”) is contained in a div with the class tombstone-container.

Time to Start Scraping!

We now know enough to download the page and start parsing it. In the below code, we will:

Download the web page containing the forecast.
Create a BeautifulSoup class to parse the page.
Find the div with id seven-day-forecast, and assign to seven_day
Inside seven_day, find each individual forecast item.
Extract and print the first forecast item.

page = requests.get("https://forecast.weather.gov/MapClick.php?lat=37.7772&lon=-122.4168")

soup = BeautifulSoup(page.content, 'html.parser')

seven_day = soup.find(id="seven-day-forecast")

forecast_items = seven_day.find_all(class_="tombstone-container")

tonight = forecast_items[0]

print(tonight.prettify())

<div class="tombstone-container">

	<p class="period-name">

		Tonight

		<br>

		<br/>

		</br>

	</p>

	<p>

		<img alt="Tonight: Mostly clear, with a low around 49. West northwest wind 12 to 17 mph decreasing to 6 to 11 mph after midnight. Winds could gust as high as 23 mph. " class="forecast-icon" src="newimages/medium/nfew.png" title="Tonight: Mostly clear, with a low around 49. West northwest wind 12 to 17 mph decreasing to 6 to 11 mph after midnight. Winds could gust as high as 23 mph. "/>

	</p>

	<p class="short-desc">

		Mostly Clear

	</p>

	<p class="temp temp-low">

		Low: 49 °F

	</p>

</div>

Extracting information from the page

As we can see, inside the forecast item tonight is all the information we want. There are four pieces of information we can extract:

The name of the forecast item — in this case, Tonight.
The description of the conditions — this is stored in the title property of img.
A short description of the conditions — in this case, Mostly Clear.
The temperature low — in this case, 49 degrees.

We’ll extract the name of the forecast item, the short description, and the temperature first, since they’re all similar:

period = tonight.find(class_="period-name").get_text()

short_desc = tonight.find(class_="short-desc").get_text()

temp = tonight.find(class_="temp").get_text()

print(period)

print(short_desc)

print(temp)

Tonight

Mostly Clear

Low: 49 °F

Now, we can extract the title attribute from the img tag. To do this, we just treat the BeautifulSoup object like a dictionary, and pass in the attribute we want as a key:

img = tonight.find("img")

desc = img['title']

print(desc)

Tonight: Mostly clear, with a low around 49. West northwest wind 12 to 17 mph decreasing to 6 to 11 mph after midnight. Winds could gust as high as 23 mph.

Extracting all the information from the page

Now that we know how to extract each individual piece of information, we can combine our knowledge with CSS selectors and list comprehensions to extract everything at once.

In the below code, we will:

Select all items with the class period-name inside an item with the class tombstone-container in seven_day.
Use a list comprehension to call the get_text method on each BeautifulSoup object.

period_tags = seven_day.select(".tombstone-container .period-name")

periods = [pt.get_text() for pt in period_tags]

periods

['Tonight',

'Thursday',

'ThursdayNight',

'Friday',

'FridayNight',

'Saturday',

'SaturdayNight',

'Sunday',

'SundayNight']

As we can see above, our technique gets us each of the period names, in order.

We can apply the same technique to get the other three fields:

short_descs = [sd.get_text() for sd in seven_day.select(".tombstone-container .short-desc")]

temps = [t.get_text() for t in seven_day.select(".tombstone-container .temp")]

descs = [d["title"] for d in seven_day.select(".tombstone-container img")]print(short_descs)print(temps)print(descs)

['Mostly Clear', 'Sunny', 'Mostly Clear', 'Sunny', 'Slight ChanceRain', 'Rain Likely', 'Rain Likely', 'Rain Likely', 'Chance Rain']

['Low: 49 °F', 'High: 63 °F', 'Low: 50 °F', 'High: 67 °F', 'Low: 57 °F', 'High: 64 °F', 'Low: 57 °F', 'High: 64 °F', 'Low: 55 °F']

['Tonight: Mostly clear, with a low around 49. West northwest wind 12 to 17 mph decreasing to 6 to 11 mph after midnight. Winds could gust as high as 23 mph. ', 'Thursday: Sunny, with a high near 63. North wind 3 to 5 mph. ', 'Thursday Night: Mostly clear, with a low around 50. Light and variable wind becoming east southeast 5 to 8 mph after midnight. ', 'Friday: Sunny, with a high near 67. Southeast wind around 9 mph. ', 'Friday Night: A 20 percent chance of rain after 11pm. Partly cloudy, with a low around 57. South southeast wind 13 to 15 mph, with gusts as high as 20 mph. New precipitation amounts of less than a tenth of an inch possible. ', 'Saturday: Rain likely. Cloudy, with a high near 64. Chance of precipitation is 70%. New precipitation amounts between a quarter and half of an inch possible. ', 'Saturday Night: Rain likely. Cloudy, with a low around 57. Chance of precipitation is 60%.', 'Sunday: Rain likely. Cloudy, with a high near 64.', 'Sunday Night: A chance of rain. Mostly cloudy, with a low around 55.']

Combining our data into a Pandas Dataframe

We can now combine the data into a Pandas DataFrame and analyze it. A DataFrame is an object that can store tabular data, making data analysis easy. If you want to learn more about Pandas, check out our free to start course here.

In order to do this, we’ll call the DataFrame class, and pass in each list of items that we have. We pass them in as part of a dictionary.

Each dictionary key will become a column in the DataFrame, and each list will become the values in the column:

import pandas as pd

weather = pd.DataFrame({

    "period": periods,

    "short_desc": short_descs,

    "temp": temps,

    "desc":descs

})

weather

	desc	period	short_desc	temp
0	Tonight: Mostly clear, with a low around 49. W…	Tonight	Mostly Clear	Low: 49 °F
1	Thursday: Sunny, with a high near 63. North wi…	Thursday	Sunny	High: 63 °F
2	Thursday Night: Mostly clear, with a low aroun…	ThursdayNight	Mostly Clear	Low: 50 °F
3	Friday: Sunny, with a high near 67. Southeast …	Friday	Sunny	High: 67 °F
4	Friday Night: A 20 percent chance of rain afte…	FridayNight	Slight ChanceRain	Low: 57 °F
5	Saturday: Rain likely. Cloudy, with a high ne…	Saturday	Rain Likely	High: 64 °F
6	Saturday Night: Rain likely. Cloudy, with a l…	SaturdayNight	Rain Likely	Low: 57 °F
7	Sunday: Rain likely. Cloudy, with a high near…	Sunday	Rain Likely	High: 64 °F
8	Sunday Night: A chance of rain. Mostly cloudy…	SundayNight	Chance Rain	Low: 55 °F

We can now do some analysis on the data. For example, we can use a regular expression and the Series.str.extract method to pull out the numeric temperature values:

temp_nums = weather["temp"].str.extract("(?Pd+)", expand=False)

weather["temp_num"] = temp_nums.astype('int')

temp_nums

0 49

1 63

2 50

3 67

4 57

5 64

6 57

7 64

8 55

Name: temp_num, dtype: object

We could then find the mean of all the high and low temperatures:

weather["temp_num"].mean()

58.444444444444443

We could also only select the rows that happen at night:

is_night = weather["temp"].str.contains("Low")

weather["is_night"] = is_night

is_night

0 True

1 False

2 True

3 False

4 True

5 False

6 True

7 False

8 True

Name: temp, dtype: bool

weather[is_night]

0 True

1 False

2 True

3 False

4 True

5 False

6 True

7 False

8 True

Name: temp, dtype: bool

	desc	period	short_desc	temp	temp_num	is_night
0	Tonight: Mostly clear, with a low around 49. W…	Tonight	Mostly Clear	Low: 49 °F	49	True
2	Thursday Night: Mostly clear, with a low aroun…	ThursdayNight	Mostly Clear	Low: 50 °F	50	True
4	Friday Night: A 20 percent chance of rain afte…	FridayNight	Slight ChanceRain	Low: 57 °F	57	True
6	Saturday Night: Rain likely. Cloudy, with a l…	SaturdayNight	Rain Likely	Low: 57 °F	57	True
8	Sunday Night: A chance of rain. Mostly cloudy…	SundayNight	Chance Rain	Low: 55 °F	55	True

Next Steps For This Web Scraping Project

If you’ve made it this far, congratulations! You should now have a good understanding of how to scrape web pages and extract data. Of course, there’s still a lot more to learn!

If you want to go further, a good next step would be to pick a site and try some web scraping on your own. Some good examples of data to scrape are:

News articles
Sports scores
Weather forecasts
Stock prices
Online retailer prices

You may also want to keep scraping the National Weather Service, and see what other data you can extract from the page, or about your own city.

Alternatively, if you want to take your web scraping skills to the next level, you can check out our interactive course, which covers both the basics of web scraping and using Python to connect to APIs. With those two skills under your belt, you’ll be able to collect lots of unique and interesting datasets from sites all over the web!

How to Configure Network Settings in Ubuntu

noreply@blogger.com (Nick) — Tue, 01 Nov 2022 04:07:00 +0000

When installing an Ubuntu server or desktop, it is important to know how to configure and view network settings. It’s also useful for troubleshooting problems with your Internet connection. Basic network configuration includes setting the IP address, the subnet mask for internal communication and a gateway for connecting to external networks. In this article, I’ll give you examples of the basic configuration you need to set up a network in Ubuntu, either from the command line or from the Ubuntu Network Manager GUI. The steps have been tested on Ubuntu 18.04 LTS up to Ubuntu 22.04 LTS, but will also work on newer Ubuntu versions.

Basic network setup requires:

Setting/Changing an IP address
Setting up/Changing Hostname
Editing a hosts file

Setting/Changing an IP address

There are several ways to set an IP address in Ubuntu. You can configure the network interface to use dynamic IP using a DHCP server or you can manually set a static IP address.

Method #1: Network configuration on the command line

In Ubuntu, you can set your IP address through terminal commands.

First type netstat -I to find the interface name. Then type the below command:

sudo ifconfig eth0 192.168.72.6 netmask 255.255.255.0

Then to add a default gateway, add the below command:

sudo route add default gw 192.168.72.1 eth0

Method #2: Network configuration using the GUI

You can set an IP address via the graphical user interface in Ubuntu. From the desktop, click on the start menu and search for Settings. From the Settings window, click on the Network tab. Then from the right pane, select the interface and click on the gear icon to open settings for that interface.

From the IPv4 tab, you can select the Automatic (DHCP) radio button to allow the system to dynamically obtain the IP address.

If you want to set a static IP address, click on the Manual radio button. Enter the IP address, subnet mask, and a default gateway. Then click on Apply to save the current changes.

Method #3: Configure the network by editing /etc/interfaces file

Here is another method that you can use to configure the IP address. To set IP address dynamically, you have to edit /etc/network/interfaces. In /etc/network/interfaces, the basic configuration of interfaces is stored.

Edit the /etc/network/interfaces by entering the following command in terminal.

sudo nano /etc/network/interfaces

Then add the following lines:

auto eth1
  iface eth1 inet dhcp

Save the file and restart networking services using the below command.

sudo systemctl restart networking

To set a Static IP address, you have to edit /etc/network/interfaces

 sudo nano /etc/network/interfaces

Add the below lines to /etc/network/interfaces.

auto eth1
  iface eth1 inet static
  address 192.168.72.8
  netmask 255.255.255.0
  gateway 192.168.72.1
  dns-nameservers 8.8.8.8 4.4.2.2

Save the file and restart networking services.

sudo systemctl restart networking

Setting up/Changing Hostname

The hostname of Ubuntu OS is configured in the file /etc/hostname.

To edit /etc/hostname, enter the below command:

sudo nano /etc/hostname

This file contains only the hostname of the file, change the name, and then save it.

Editing the /etc/hosts file

Hosts file maps hostname to IP address locally. For instance, you have a server in your local network, instead of remembering its IP, you can map its IP with a name in your /etc/hosts file. It will allow you to access that machine with a name instead of the IP.

To edit a hosts file, enter:

sudo nano /etc/hosts

Add the server IP address and name in the hosts file in the following format.

192.168.72.10 fileserver

Save the file and reboot the system to apply the changes.

That’s all you need to set up a network in Ubuntu. Those were the basic settings. There are many more options you can configure in your Ubuntu machine.

How to Configure Network Settings in Ubuntu

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