Bash - Login Shell

A login shell:

• behaves as if the user were login and calls the login script
• will execute at the end of the session a logout script

A login shell is a shell:

• whose first character of argument zero ($0) is a -
• or started with the –login or -l option. See Bash - Bash cli

When bash is invoked as:

• an interactive login shell,
• or as a non-interactive shell with the –login option,

it reads and executes commands from the following files in this order:

• /etc/profile,
• ~/.bash_profile,
• ~/.bash_login,
• and ~/.profile,

The file must exists and be readable.

The –noprofile option may be used when the shell is started to inhibit this behavior.

When a login shell exits, bash reads and executes commands from the files:

• ~/.bash_logout
• and /etc/bash.bash_logout

if the files exists.

In a script, you can test if the shell is a login shell with this predicate.

argv[0][0] == '-'

• Difference between Login Shell and Non-Login Shell?