TableOfContents

Global Environment Variables

These may be put in one of these files:

• /etc/profile
• /etc/environment

To append 'testbin' to the PATH environment variable and to set a variable called JAVA_HOME and append it to PATH:

export JAVA_HOME="/usr/lib/j2sdk1.5-sun"

(A colon followed by no directory is treated as the current working directory)
export PATH="$PATH:/home/user/testbin:$JAVA_HOME/bin:"

Session Specific Environment Variables

You may sometimes want variables defined locally (eg: restricted to your accounts shell only) and not globally (all users). So just append whatever variables you need defined to your ~/.bashrc file.

Bash Shell Environment Variables

• when starting a shell after you've logged in already, either from the console or thru X display manager, that shell will be non-login, and only reads /etc/bash.bashrc and ~/.bashrc.
• when the user starts a bash shell by logging into a console, this starts a login shell, which will read /etc/profile, ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order. Bash reads and executes commands from the first one that exists and is readable. The `--noprofile' option may be used when the shell is started to inhibit this behavior.

• If Bash is invoked with the name sh, whether as an interactive login shell, or as a non-interactive shell with the --login' option, it first attempts to read and execute commands from /etc/profile' and `~/.profile', in that order.

References

• [http://www.gnu.org/software/bash/manual/bashref.html Bash Reference]

• [http://www.gentoo.org/doc/en/handbook/handbook-x86.xml?part=2&chap=5 Environment Variables @Gentoo Wiki]