Linux Ubuntu for Daily Life :)

How to Delete One Word in Terminal

2011-09-12T21:34:00.000-07:00

Every day working with Terminal, we need a lot of shortcut to speed up our task. One of my frequently used shortcut is deleting one word in the left side of cursor:

Alt + Backspace

Enjoy!

How to Delete One Line in Vim

2011-09-12T03:32:00.000-07:00

This is the way I delete one line in Vim

:d

Enjoy!

[Ubuntu] How to Launch Network Proxy Properties in Terminal

2011-05-27T03:57:00.000-07:00

I want to bypass System*Preferences*Network Proxy by using a command line interface in Terminal. After hacking Ubuntu Alt+F2 and command completion in Terminal for a while, I found the way how to launch Network Proxy Properties in Terminal. Here is the command line:

$ gnome-network-properties

Enjoy!

How to Check Ubuntu Version in Terminal

2011-05-10T02:31:00.000-07:00

I just curious about how to check Ubuntu version via Terminal. Since I often remote a server and I don't know what version is. Here is the command:

lsb_release -a

Then it will print out some messages like this:

No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 11.04
Release: 11.04
Codename: natty

So I has already know what Ubuntu version used in server. It is Natty. Enjoy!

Warning: Remote Host Identification has Changed!

2011-05-10T02:22:00.001-07:00

When we remote a server using ssh, sometimes we get a warning message like this:

Warning: Remote Host Identification has Changed!

What should we do? Just follow a command below the warning.

ssh-keygen -f "/home/hudan/.ssh/known_hosts" -R server_ip_address

Enjoy :).

How to Upgrade to Natty

2011-05-09T22:49:00.000-07:00

Usually, I upgrade my Ubuntu box by first changing source list file. Then issuing this two simple command in Terminal:

sudo apt-get update
sudo apt-get dist-upgrade

Unfortunately, when I upgrade my Maverick to Natty, those two don't work. Then I googled it and find simpler method. Here we go:

# Look for Update Manager menu. Then click Install Update button (it is located in bottom left of dialog box).

# Wait for approximately three hours (this is based on your internet speed)

# Restart your PC.

Welcome to the new look of Natty. Enjoy!

Network Proxy: Apply System-Wide

2011-05-09T22:39:00.000-07:00

In several latest version of Ubuntu, we have Network Proxy Preferences menu. In this article, I want to show the effect of Apply System-Wide option. One of this effect is when we work in Terminal.

# Before applying system-wide proxy, try echoing proxy in Terminal and it will show nothing

echo $http_proxy

# After choosing this option, close Terminal. Then try echoing again and you will get message like this

http://username:password@proxy_ip_address:port/

It means you have applied proxy system-wide option. Enjoy!

Ubuntu Arabic Keyboard Layout

2011-05-05T07:19:00.000-07:00

Just wanna share Arabic keyboard layout in Ubuntu. Maybe you want to print it or just to look at it :). Don't forget to click the image to enlarge.

Enjoy!

How to Set Skype Proxy in Ubuntu

2011-05-05T06:56:00.000-07:00

Hi... we are still talking about proxy :). Now, we want to play Skype and we have to set proxy first. This how-to has been tested in Ubuntu Maverick Meerkat. Here we go:

# When you launch Skype, you will get icon in your top-right panel

# Right click it and choose Options

# Change proxy ip address, username, and password as appropriate (click image to enlarge)

We are done here :). Enjoy!

Export Proxy in Ubuntu Terminal

2011-05-01T07:23:00.000-07:00

Before working with http proxy, you must set it first. When you are on terminal mode, here we go:

export http_proxy="http://proxy_ip_address:port"
export http_proxy_user=username
export http_proxy_passwd=password

Enjoy!

A Nice Blog About Blogger

2011-04-27T07:03:00.000-07:00

There is a nice blog about Blogspot. If you use Blogger as free blog, you should check this blog: http://blogknowhow.blogspot.com/. There are so many resource about styling, monetizing, and optimizing your blogspot space.

Let's check it out and enjoy!

How to Tunnel SSH via HTTP Proxy

2011-04-27T04:57:00.000-07:00

I have to access ssh server but there is http proxy when I want to go to internet. How can I tunnel ssh via http proxy? Here are the way to do it:

# Download corkscrew. It is easy tool for tunneling SSH through HTTP proxies

# Extract corkscrew then configure and install it

tar -xzvf corkscrew.tar.gz
cd corkscrew
./configure
make install

# Create ~/.ssh/proxyauth file and set authentication for http proxy server

username:password

# Open ~/.ssh/config file. Add proxy server ip address and its authentication in proxyauth file like this:

Host *
ProxyCommand corkscrew proxy_ip_address proxy_port %h %p ~/.ssh/proxyauth

# Try to access your server via ssh

ssh username@example.com

And it's all done. Enjoy!

Apache Rewrite Modul Problems in Linux Ubuntu

2011-04-18T07:22:00.000-07:00

I often have a problem with rewrite modul in Apache. When you have the same problem like me, you should check:

# RewriteBase syntax in .htaccess

# "Allow all" option in /etc/apache2/sites-enabled directory. Here are the example of 000-default file in sites-enabled directory (in tag Directory "/var/www/somedir"):

   Order allow,deny
  Allow from all
  AllowOverride All

# Is .htaccess file executable?

# Make sure rewrite module is loaded in Apache. When this module successfully loaded, it will appear in mods-enabled directory as rewrite.load file. You can load them by issuing:

sudo a2enmod rewrite

Just double check them. Enjoy!

First Timer RabbitVCS Subversion Client

2011-04-13T05:25:00.000-07:00

After setting proxy in RabbitVCS, I have a folder that contains app files to be versioned. How can we add these files to our subversion server?

# Right click in the folder, choose Checkout

# Set subversion servers, for example: https://example.com/svn/apps

# Set directory to be versioned

# Click OK or Finish.

Then we can submit all of app files by right-clicking the folder and choose Commit. Select or deselect any files you want to Commit. Wait a moment and you're done versioning your app files for the first time. Enjoy!

How to Set Proxy in RabbitVCS Subversion Client

2011-04-13T05:05:00.000-07:00

I use RabbitVCS as subversion client in my little Ubuntu box. Since I should work behind proxy, I have set up proxy username and password in RabbitVCS. Don't forget to be root to configure :).

# Go to /etc/subversion

cd /etc/subversion

# There are two files: servers and config. Open servers file

vi servers

# Find [global] section and set proxy host, username, and password

[global]
http-proxy-host = proxy_ip_address
http-proxy-port = proxy_port
http-proxy-username = username
http-proxy-password = password

And you're ready to version your apps. Enjoy!

How to Execute Wget Behind Proxy

2011-04-11T03:29:00.001-07:00

Two days getting headache because of working behind proxy, here is one of the result: wget command with using proxy option enabled.

wget --proxy-user=username --proxy-passwd=password
http://example.com/file.zip

Don't forget to set your proxy first. Enjoy!

Curl Using Proxy in Linux Console

2011-04-11T03:25:00.000-07:00

Going crazy using Linux console? Here is how to use curl in console behind proxy.

curl -x proxy_ip_address:port -U username:password http://example.com

Enjoy!

How Many Watt Consumed in Ubuntu Laptop?

2011-04-10T03:19:00.000-07:00

Yay... we will estimate how many watt consumed in Ubuntu laptop using data from ACPI interface. We have measured voltage and current, getting exact value of them, trying to make a simple shell script, and installing calculator package in console.
By putting all of these stuffs altogether, we will estimate how many power used by our lovely Ubuntu box.

# Make a shell script to cat voltage and ampere usage

#!/bin/bash
cat /proc/acpi/battery/C1AC/state | grep "present voltage" |
awk '{print $3}'
cat /proc/acpi/battery/C1AC/state | grep "present rate" |
awk '{print $3}'

# Make two variables to store voltage and ampere value

volt=`cat /proc/acpi/battery/C1AC/state | grep "present voltage" |
awk '{print $3}'`
ampere=`cat /proc/acpi/battery/C1AC/state | grep "present rate" |
awk '{print $3}'`

# Divide variable volt and ampere by 1000 because it still in mV or mA unit

volt=`echo "scale=3;$volt/1000"|bc`
ampere=`echo "scale=3;$ampere/1000"|bc`

Parameter scale is used to set precision. If we set them to 3, then we will get three decimal places precision.

# Measure the power by simply multiply voltage and current consumed

power=`echo "scale=3;$v*$a"|bc`

# And the full shell script is illustrated below:

#!/bin/bash
volt=`cat /proc/acpi/battery/C1AC/state | grep "present voltage" |
awk '{print $3}'`
ampere=`cat /proc/acpi/battery/C1AC/state | grep "present rate" |
awk '{print $3}'`
volt=`echo "scale=3;$volt/1000"|bc`
ampere=`echo "scale=3;$ampere/1000"|bc`
echo "Present voltage: " $volt "Volt"
echo "Present current: " $ampere "Ampere"
power=`echo "scale=3;$volt*$ampere"|bc`
echo "Present power  :" $power "Watt"

# And it will give us a message like this:

Present voltage:  16.285 Volt
Present current:  1.507 Ampere
Present power  : 24.541 Watt

This shell script has been tested in Ubuntu Lucid Lynx 10.04 and it works well. Enjoy!

[Linux Ubuntu] Getting Exact Value of Voltage and Current

2011-04-10T03:07:00.000-07:00

We are now one step closer to measuring power process. In the previous explanation, we have got voltage and current value but it still has some obstacles. I mean, there are string "present voltage:" and "present rate" in voltage and current value, respectively. How can we remove them? We employ grep to get certain line and we can use awk get certain column of one line output.

cat /proc/acpi/battery/C1AC/state | grep "present voltage" |
awk '{print $3}'

cat /proc/acpi/battery/C1AC/state | grep "present rate" |
awk '{print $3}'

$3 in awk means it only prints the third column. The value of first column is string "present" and the second one is "voltage" or "rate" in current value. This command will print the exact value only without obstacles. Enjoy!

How to Make a Shell Script in Linux?

2011-04-10T02:31:00.000-07:00

Yeah, like you say, it's for newbie only :D. We will make a shell script to display voltage in mV and current in mA like I post before. Shell script can contain one or more lines of instruction usually issued in Terminal.

# Open your editor (I always choose vi) type:

#!/bin/bash
cat /proc/acpi/battery/C1AC/state | grep "present voltage"
cat /proc/acpi/battery/C1AC/state | grep "present rate"

# Don't forget to replace "C1AC" with your own battery type

# Save these shell script, for example, myfile.sh

# Change the mode of file so that it can be executed

chmod +x myfile.sh

# Run this script by typing this instruction in your Terminal:

./myfile.sh

# The output will look like this:

present voltage:         16778 mV
present rate:            702 mA

Shell script will simplify our life. Believe me and enjoy!

How Many Volt Consumed by Ubuntu Laptop?

2011-04-10T02:17:00.000-07:00

Now we will observe how many watt consumed by Ubuntu laptop. Similar with how to check current (in ampere) consumed, we will only replace the grep command.

# Goto /proc/acpi/battery directory and go to directory name based on your battery type (i.e. C1AC)

cd /proc/acpi/battery/C1AC

# Cat the content of state file and grep only the voltage

cat state | grep "present voltage"

# We will get output like this:

present voltage:         16410 mV

The voltage consumed is shown in mV. Enjoy!

How Many Ampere Consumed by Ubuntu Laptop?

2011-04-10T01:59:00.000-07:00

We can monitor how many ampere consumed by our Ubuntu laptop. Unfortunately, we still can't do them in Ubuntu desktop. ACPI interface will be used to employ this technique.

# Goto /proc/acpi/battery directory

cd /proc/acpi/battery

# There is only one directory and the name is different in accordance with laptop specifications. For example, my folder name is C1AC.

cd C1AC

# You will see three files: alarm, info, and state. Try to show the content of "state" file

cat state

# You will get a technical state about battery like shown here:

present:                 yes
capacity state:          ok
charging state:          charging
present rate:            1505 mA
remaining capacity:      840 mAh
present voltage:         16410 mV

# We only want to get ampere used, so just grep them

cat state | grep "present rate"

# The output is ampere present rate shown in mA

present rate:            1505 mA

We will use this technique to get power (in Watt) consumed by Ubuntu laptop. Enjoy!

Is There any Calculator in Terminal?

2011-04-10T01:15:00.000-07:00

Yeah, absolutely. You can use bc package in Linux Ubuntu. This is an arbitrary precision calculator language. Or, we can just call it "bash calculator" (bc). Simply issue this command:

apt-get install bc

Of course you have to be a root when issuing it. Now we will try bc to perform simple arithmetic operation, such as:

echo 2+3 | bc
echo 2-3 | bc
echo 2*3 | bc
echo 6/2 | bc

Run them in terminal and you will get output: 5, -1, 6, and 2. We will use this calculator later in the next tutorial. Enjoy!

[Linux Ubuntu] How to Put Harakat or Vowel Marks in Arabic Keyboard Layout

2011-04-10T00:38:00.000-07:00

Now, you are able to enable Arabic keyboard layout and write them in Linux Ubuntu. What about adding harakat or vowel marks in Arabic? Follow these steps:

# Write the word first. For example, word "Al 'Ilmu"

العلم

# We should put fatha in character " ا ". To do this, put cursor behind character " ا ".

# In the Arabic keyboard layout, fatha is placed in character Shift + Q. So, press Shift + َQ and you will get: " اَ "

# Now put the cursor behind character " ل " and add sukun mark by pressing Shift + X. You will get: اَلعلم

# Continue these steps until all of word is fulfilled with appropriate harakat (اَلْعِلْمُ). Enjoy!

How to Write Arabic in Linux Ubuntu

2011-04-10T00:24:00.000-07:00

How to write Arabic in Linux Ubuntu? First, you should enable Arabic keyboard layout. The Arabic keyboard layout will look like this picture (click to enlarge):

# Then, open your favorite text editor. I prefer gedit (Applications*Accessories*gedit Text Editor)

# Click Keyboard Preferences (usually it is placed in top-right of desktop panel) and it will be switched from USA to Ara

# Type your word one by one based on Arabic keyboard layout. It will be connected automatically.

# Type Space key to separate one word to another.

It is easy, isn't it? Enjoy!