|Bash and Its Startup File Execution Algorithm|
A login shell is one whose first character of argument zero is a -, or one started with the --login option.
An interactive shell is one started without non-option arguments and without the -c option whose standard input and error are both connected to terminals (as determined by isatty(3) ), or one started with the -i option. PS1 is set and $- includes i if bash is interactive, allowing a shell script or a startup file to test this state.
When bash is invoked as an interactive login shell, or as a non-interactive shell with the --login option, it first reads and executes commands from the file /etc/profile, if that file exists.
After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order, and reads and executes commands from the first one that exists and is readable. The first 2 files do not exist in my setup, so it runs ~/.profile.
When a login shell exits, bash reads and executes commands from the file ~/.bash_logout, if it exists.
When an interactive shell that is not a login shell is started, bash reads and executes commands from /etc/bash.bashrc and ~/.bashrc, if these files exist.
This may be inhibited by using the --norc option. The --rcfile file option will force bash to read and execute commands from file instead of /etc/bash.bashrc and ~/.bashrc.
Files run ... If ... 1st: /etc/profile Interactive login shell 2nd: ~/.profile 3rd: ~/.bashrc Interactive non-login shell
When bash is started non-interactively, to run a shell script, for example, it looks for the variable BASH_ENV in the environment, expands its value if it appears there, and uses the expanded value as the name of a file to read and execute.
Thus, bash behaves as if the following command were executed:
if [ -n "$BASH_ENV" ]; then . "$BASH_ENV"; fi
but the value of the PATH variable is not used to search for the file name.
Given a shell script like:
#!/bin/bash . ~/.profile . ~/.bashrc echo Hi
Bash will run ~/.profile, but when it runs ~/.bashrc, it hits this at the top:
# If not running interactively, don't do anything [ -z "$PS1" ] && return
which means ~/.bashrc does nothing. This in turn means ~/.bash_aliases and /home/ron/perl5/perlbrew/etc/bashrc are not run.
In my setup, ~/.profile also sources ~/.bashrc, but that too does nothing.
If you want to set $LD_LIBRARY_PATH (say to use Perl's BerkeleyDB), or $PATH (say to add ~/bin or use Oracle's BerkeleyDB programs), you should do this in ~/.profile. This makes the changes available even when ~/.bashrc does not run.
Executed by ~/.bashrc.
Executed by bash for login shells. This file is not read by bash, if ~/.bash_profile exists. ~/.bash_login does not exist in my setup. Neither does ~/.bash_profile.
Executed by bash when login shell exits. This file does not exist in my setup.
Executed by bash for login shells. This file does not exist in my setup.
Executed by bash for non-login shells. E.g. run by /usr/bin/gnome-terminal. Also, in my setup, ~/.profile runs ~/.bashrc.
Executed by bash for non-login shells.
Executed by bash for login shells.
Executed by ~/.bashrc.
Executed by bash for login shells. This file is not read by bash, if ~/.bash_profile or ~/.bash_login exists. The latter 2 files do not exist in my setup, so it runs ~/.profile. E.g. run by /usr/bin/xterm. Also, in my setup, ~/.profile runs ~/.bashrc.