LINUX for neophyte

Backup online data using Backupify

noreply@blogger.com (Lemuel) — Thu, 28 Jan 2010 13:22:00 +0000

It's time for you to backup all of your online sites, like facebook, flickr, google docs and other sites that you store online. You'll never know when something happens on these sites. And good thing that Backupify is doing this kind of service. They are offering a free account sign-up until January 31, 2010.
Backupify is very easy to use, after sign-up you can configure the sites you want to backup. It's using Amazon webservices, so I think and believe that it's a good quality.

Here are the supported sites:

Gmail
Google Docs
Twitter
Flickr
Facebook
Basecamp
Wordpress
Delicious
Photobucket
Blogger
Friendfeed

It will alert you through email when backup is finished. I have tried it and started to like it. With the advent of technology, rule of the thumb is you need to have three backup location, your computer/laptop, your on-line sites and your on-line backup.

Act now and act fast. Backup! Backup! Backup!

Linux howTo: How to check your Computer's temperature

noreply@blogger.com (Lemuel) — Fri, 08 Jan 2010 14:54:00 +0000

There are times that you want to check your computer's temperature or server. You can check it with a simple command:

user@linux$ cat /proc/acpi/thermal_zone/THRM/temparature

temperature: 40 C

user@linux$

Note that this method works only if ACPI (Advanced Configuration and Power Interface) thermal zones are supported on your computer.

Linux Tip: Linux monitor processes using kill

noreply@blogger.com (Lemuel) — Wed, 06 Jan 2010 13:52:00 +0000

One of the tasks of an Administrators or even users of Linux server, workstations and desktop is to monitor running processes. Processes that are important to your production Linux servers. One of the command that I recently learn that can help in monitoring linux processes is the kill -0 command. But wait, kill means terminate the process. How can we monitor the process if we use the kill command?

When you refer to the manual/info of kill, 0 means no signal will be sent, it will not terminate the process. By combining return status(echo $?) with kill -0, you can check if a certain process is running or not.

Open a gnome-terminal and login as root or use sudo for Ubuntu user.
All processes running (UNIX daemon) are at /var/run directory. So when you want to check the process id(pid) of yum daemon, just look into the file /var/run/yum.pid.

    root@linux# cat /var/run/yum.pid
    1755
    root@linux#

Do the following command when checking the status of process:

    root@linux# kill -0 1755
    root@linux# echo $?
    0
    root@linux#

If the output of echo $? is 0, that means the process is running. Refer to my other post regarding $? variable here.

To shorten the above procedure, we can just do this:

    root@linux# kill -0 $(cat /var/run/yum.pid)
    root@linux# echo $?
    0
    root@linux#

Daemon is not running ( yums.pid doesn't exist )

    root@linux# kill -0 $(cat /var/run/yums.pid)
    cat: /var/run/yums.pid: No such file or directory
    root@linux# echo $?
    1
    root@linux#

You can now monitor processes with kill -0 command. Just play around, it will help in some unexpected situations.

Pidgin, chat client for Linux

noreply@blogger.com (Lemuel) — Sat, 26 Dec 2009 14:41:00 +0000

If you are looking for a good chat client for Linux, I suggest you use the Pidgin. It's user friendly and easy to use.

Pidgin is a chat client account for Windows, Linux and other UNIX operating system.

It let's you manage an accounts on multiple chat network. Compatible with the following chat networks:AIM, ICQ, Google Talk, Jabber/XMPP, MSN Messenger, Yahoo!, Bonjour, Gadu-Gadu, IRC, Novell GroupWise Messenger, QQ, Lotus Sametime, SILC, SIMPLE, MySpaceIM, and Zephyr. It can support many more with plugins.

There are two easy ways to install it( do this as root ) using a Fedora Core 11:

1.Through yum command

   root@penguin$ yum install pidgin

   It will get all the necessary package and dependencies for pidgin.

   If you are using Fedora Core 4, 5, 6 or 7 follow this steps from pidgin site

2. Through Add/Remove Software GUI

   Go to System->Add/Remove Software

Enter 'pidgin' in the find entry form, press find. It will show a lists related to your keyword search. Find the Pidgin, select it and press apply button. It will install and download all the dependencies

After installing it. Pidgin will appear at Applications->Internet->Pidgin

You can now start to add your accounts and enjoy...

For Ubuntu users you can follow this link from pidgin http://pidgin.im/download/ubuntu/

Feel free to drop a comments...

source : pidgin.im

Linux distros: available Linux distros

noreply@blogger.com (Lemuel) — Thu, 24 Dec 2009 08:03:00 +0000

Question : What are the different popular Linux distributions?

Answer :

Fedora - developed by community-supported Fedora Project and sponsored by Red Hat.
Ubuntu - sponsored by UK based company Canonical Ltd. It is based on Debian/Linux distribution system.
Linux Mint - based on Ubuntu with integrated media codecs. Founded by Clement Lefebvre
CentOS - community supported based on Red Hat Enterprise Linux
Debian - a GNU/Linux based distro
Gentoo - based on either Linux or FreeBSD that can be automatically optimized and customized for just about any application.

You can try them and differentiate their capability. For beginners, use the Ubuntu and Linux Mint, they have a good desktop user experience.

source : wikipedia.com

Linux howTo: How to see Linux Unix command manual?

noreply@blogger.com (Lemuel) — Sun, 20 Dec 2009 09:51:00 +0000

Question: How to see Linux / Unix command manual?

Answer:
Linux / Unix commands have built-in manuals. Just do the following command

user@penguin$ man top

man is a built in command for Linux. man will check if there is top document, if it has it will load the on-line manual pages in the command line.

This is the result of the above command:

top(1)
NAME
   top - display and update sorted information about processes

SYNOPSIS
   top [-a | -d | -e | -c ]
   [-F | -f]
   [-h]
   [-i ]
   [-k]
   [-L | -l ]
   [-o ] [-O ]
   [-p ] [-P ]
   [-R | -r]
   [-S]
   [-s ]
   [-T | -t]
   [-U ]
   [-u]
   [-W | -w]
   [-X | -x]
   [[-n] ]

Feel free to add a comment.

Linux question: command or script exit status

noreply@blogger.com (Lemuel) — Fri, 18 Dec 2009 11:50:00 +0000

Question: What is exit status of shell or command in Linux?

Answer:
Every time a process or shell exit, it will send a terminating code to the operating system. This is what they call 'exit status'. We can detect wether the command is successful or not by checking the exit status. Here's how you can check:

user@penguin$ echo "Hello World"
Hello World
user@penguin$ echo $?
0
user@penguin$

$? is a variable where Linux stores the exit status of the previous command it ran.
0 in exit code is successful. If greater than 0, it means that it was exited abnormally or there's an error.

user@penguin$ ech "Hello World"
-bash: ech: command not found
user@penguin$ echo $?
127
user@penguin$

ech is not a linux command. And the exit code is greater than 0 because of the error.
Try to play with it. This will be a great help for your linux knowledge.

Feel free to post a comment.

Linux howTo: shell sccripting part 1

noreply@blogger.com (Lemuel) — Wed, 16 Dec 2009 14:28:00 +0000

In this post we will walk through the different parts of shell scripting. It is intended for beginners and those folks who want a refresher. We will use any text editor you like ('vi' is also ok).

Difficulty: Basic

So let's start. Open your favorite editor. Copy and paste the following code block(red font).

#! /bin/sh
# my first script

echo "Hello World"
exit 0

Save it as scriptpart1.sh, we use the .sh file extension so that we know that this file is a shell script. After saving the file. We need to make the file executable.
At the command line type the following and press enter

user@penguin$ chmod 755 scriptpart1.sh

You can now execute the script.

user@penguin$ ./scriptpart1.sh
Hello World
user@penguin$

You should see the Hello World at the command line after you press enter.

Let's start understanding every line of the script

#! /bin/sh

Is the entry point of the script. #! is also known as shebang while /bin/sh is the interpreter. It will use the /bin/sh environment.

/bin/sh is known as Bourne shell.

/bin/csh is known as C shell.

/bin/bash is known as Bourne-again shell.

There are lots of unix shell but our main focus is the Bourne shell.

How to know the complete path of the interpreter we are using?

Answer: At the command line type 'which sh' and press enter

user@penguin$ which sh

/bin/sh

user@penguin$

In this machine that I'm using, the sh path is at /bin/sh. We can now move on to the next line which is:

# my first script

This line is a comment one. You can actually put some notes in the script. Note that #! is not a comment. Comment is very useful, you can put anywhere in your code. Standard practice is to put a short and precise comment.

Next part is the blank line. Shell script will ignore the blank line and it will go to the next line. Next line is the echo line.

echo "Hello World"

echo in Linux means displaying the word in the command line. That's why we have 'Hello World' displayed after we ran the script.

We are almost done. You can now display messages using the echo command.

Last part is the exit.

exit 0

It will exit the script. And the number 0, it will tell to the Linux current process that the script exited at 0, meaning successful. We will elaborate next time regarding the exit code of commands and script.

So that's how we write a script. Till next time. Feel free to comment on this post.