How to Create Environment Variables in Linux

Dagu — Sun, 19 Apr 2009 05:39:00 +0000

This tutorial is still about creating environment variables, just like my last tutorial. But now I create environment variable in Linux, not Windows.

To create or edit environment variable in linux is very easy. You may create or edit environment variable from terminal.

The syntax is: export VAR_NAME=var_content

For example:

export JAVA_HOME=/usr/lib/jvm/sun-java6

Yes, very easy right? If you want to append content to an existing variable, you can’t use command above. Command above will create a new variable, not append it. To append content, you may use command below.

The syntax is: export VAR_NAME=$VAR_NAME:var_content

For example:

export PATH=$PATH:/usr/lib/jvm/sun-java6/bin

or, if you have created JAVA_HOME variable, you may use command below:

export PATH=$PATH:$JAVA_HOME/bin

Easy right?

Note:
To define a variable, you don’t need ‘$‘ character. But when you use it (for example when you append variable content), don’t forget ‘$‘ character.

Checking Disk Capacity in Linux

Dagu — Tue, 13 Nov 2007 05:14:00 +0000

In my work, I should be familiar with linux server. Because it uses CLI (Command Line Interface), then it’s a bit difficult to use. One of my problems is how to check disk capacity. Previously, my friend had told me, but I forget it :(. In order not to forget it, I will share it in my blog. So, if I forget it, I only need to open my blog.. :)

Command to check disk capacity is df. Short description: df – report filesystem disk space usage. Use man df to get more information.

Usage example:

$ df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/sda1             14877092   9090552   5018636  65% /
/dev/shm               1037556         0   1037556   0% /dev/shm
/dev/sdb1             68890968  24462748  40872236  38% /home
/dev/sda5             14877060   6418492   7690664  46% /var

Oops, it’s not clear enough. To make it clear, add -h parameter.

$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              15G  8.7G  4.8G  65% /
/dev/shm             1014M     0 1014M   0% /dev/shm
/dev/sdb1              66G   24G   39G  38% /home
/dev/sda5              15G  6.2G  7.4G  46% /var

Hmm… it’s better, isn’t it?