41

Are the concepts of login/non-login shells the same as the concepts of non-interactive/interactive shells (respectively)?

Or are the concepts orthogonal yielding four different combinations?

I am trying to get a clear picture of which .bashrc, .bash_profile scripts get sourced under various circumstances and I find that articles sometimes use these concepts interchangeably.

1
  • 2
    Specifically focusing on which scripts are sourced makes this a worthwhile question.. could the title be edited?
    – KCD
    Commented Jul 19, 2018 at 1:51

1 Answer 1

73
  • login shell: A login shell logs you into the system as a specific user. Necessary for this is a username and password. When you hit ctrl+alt+F1 to login into a virtual terminal you get after successful login: a login shell (that is interactive). Sourced files:

    • /etc/profile and ~/.profile for Bourne compatible shells (and /etc/profile.d/*)
    • ~/.bash_profile for bash
    • /etc/zprofile and ~/.zprofile for zsh
    • /etc/csh.login and ~/.login for csh
  • non-login shell: A shell that is executed without logging in. Necessary for this is a current logged in user. When you open a graphic terminal in gnome, it is a non-login (interactive) shell. Sourced files:

    • /etc/bashrc and ~/.bashrc for bash
  • interactive shell: A shell (login or non-login) where you can interactively type or interrupt commands, for example, a gnome terminal (non-login) or a virtual terminal (login). In an interactive shell the prompt variable must be set ($PS1). Sourced files:

    • /etc/profile and ~/.profile
    • /etc/bashrc or /etc/bash.bashrc for bash
  • non-interactive shell: A (sub)shell that is probably run from an automated process. You will see neither input nor output when the calling process doesn't handle it. That shell is normally a non-login shell, because the calling user has logged in already. A shell running a script is always a non-interactive shell, but the script can emulate an interactive shell by prompting the user to input values. Sourced files:

    • /etc/bashrc or /etc/bash.bashrc for bash (but, mostly you see this at the beginning of the script: [ -z "$PS1" ] && return. That means don't do anything if it's a non-interactive shell).
    • depending on shell; some of them read the file in the $ENV variable.
7
  • Nice explanation, but I still don't know why "That shell is normally a non-login shell, because the calling user has logged in already"?
    – L_K
    Commented Jun 20, 2017 at 2:41
  • Is there an easy way to add scripts to be run in non-interactive shells?
    – ceztko
    Commented Jun 18, 2018 at 10:36
  • Nothing clean, but see superuser.com/q/1205681/81584
    – KCD
    Commented Jul 19, 2018 at 1:54
  • 1
    [ -z "$PS1" ] is an unsafe way of checking for interactive mode, because it could be part of the environment. [[ $- != *i* ]] is more secure.
    – Bachsau
    Commented Jul 18, 2020 at 9:52
  • @Bachsau "/etc/bash.bashrc and ~/.bashrc are also run in non-interative shells." -- I'm confused. man bash says /etc/bash.bashrc and ~/.bashrc are only executed for interactive (non-login) shells. The comments in /etc/bash.bashrc (on Ubuntu 22.04) say the same.
    – balu
    Commented Jan 13 at 2:05

Not the answer you're looking for? Browse other questions tagged .