Bash rc and profile

Bash is an sh-compatible command language interpreter that executes commands read from the standard input or from a file. It has following rc and profile files, the files begain with ~ is the user level files, the content inside only effective for the user.

  • /etc/profile
  • /etc/bash.bashrc or /etc/bashrc
  • /etc/bash.bash.logout
  • ~/.bash_profile
  • ~/.bashrc
  • ~/.bash_logout
  • ~/.inputrc

Invocation

When you run bash as interactive login shell or as a non-interactive shell with --login option, it first reads and executes commands from the file /etc/profile, after this it looks for ~/.bash_profile, ~/.bash_login and ~/.profile, this is the order. An interactive login shell can be invoked by a ssh login.

But as my test on Ubuntu/CentOS, it will also looks for ~/.bashrc if these three files do not exist, in most Linux distributions there are no .bash_profile, .bash_login and .profile. If .bash_profile exist, the .bashrc file will be not read and executed. So my suggestion is do not create .bash_profile in your $HOME directory.

When you run bash as interactive shell that is not a login shell, it reads and executes command from /etc/bash.bashrc and ~/.bashrc.

In most Linux distribution, /etc/profile will invoke /etc/bash.bashrc and /etc/profile.d/*.sh or /etc/bash.bashrc invokes /etc/profile.d/*.sh, so mostly you will not feel different in interactive login shell and interactive no-login shell.

If you have questions about Bash, you can simply run man bash and find the answers.

Bash completion

There is a package bash-completion, it used to auto complete your program subcommands and arguments. If you want to auto complete your program you can simply put a complete file under /etc/bash_completeion.d. It will be invoked by /etc/profile.d/bash_completion.sh indirectly.

Bash environment

If your program is installed in non-standard system directory like /opt/your_prog, your program commands and libraries can’t be used without the prefix, so you need to add them to PATH and LD_LIBRARY_PATH. You can simply create a file /etc/profile.d/your_prog.sh, the content is very like following:

#!/bin/bash

export PATH=$PATH:/opt/your_prog/bin
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/your_prog/lib
export PYTHONPATH=/opt/your_prog/python2.7/site-packages

A little more

The rc in Linux stands for run commands.

http://superuser.com/questions/173165/what-does-the-rc-in-bashrc-etc-mean