debian : read order of bash session configuration files inconsistent

The three files are read in this order?

.bash_profile
.profile
.bashrc

This is not happening when I first open a terminal.

I have trace statements in the files appending to the file init.log. Please take a look at the following. It begins after opening a terminal. I have placed a comment to show where the log picks up after the su command.

<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="314245544159545f7155545358505f">[email protected]</a>:~$ cat init.log
reading .bashrc
done reading .bashrc
<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="314245544159545f7155545358505f">[email protected]</a>:~$ su - stephen
Password: 
<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="d1a2a5b4a1b9b4bf91b5b4b3b8b0bf">[email protected]</a>:~$ cat init.log
reading .bashrc
done reading .bashrc
#
# after su
#
reading .bash_profile
reading .profile
reading .bashrc
done reading .bashrc
done reading .profile
done reading .bash_profile
<a href="https://getridbug.com/cdn-cgi/l/email-protection" class="__cf_email__" data-cfemail="44373021342c212a042021262d252a">[email protected]</a>:~$

So the su – login triggers the expected sequence however the initial login reads only the bashrc. This cannot be correct. Can someone explain under what conditions this would occur. I could modify the bashrc and profile files so that the initial read includes all expected files but I would rather get to the root of the problem and fix it there.

Answers:

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Method 1

The answer is that bash will look for these three files (in slightly different situations) but will typically only execute one of them.

When running a login shell (typically when you log in on a terminal, or when you open a GNOME Terminal or similar, or when you use su -), more specifically an interactive login shell, then it will execute the system-wide /etc/profile and after that’s done, it will look for ~/.bash_profile, ~/.bash_login or ~/.profile and execute the first of those that it finds.

From the bash man page:

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

When bash is executed as an interactive shell, more specifically an interactive non-login shell, then it will read ~/.bashrc and execute that file.

From the bash man page:

When an interactive shell that is not a login shell is started, bash
reads and executes commands from ~/.bashrc, if that file exists.
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 ~/.bashrc.

What Linux distributions usually do is ship ~/.bash_profile, ~/.profile and ~/.bashrc files that chain each other, so that you have more consistent behavior without having to duplicate settings between the files…

For instance, Debian’s default ~/.profile contains this snippet:

# if running bash
if [ -n "$BASH_VERSION" ]; then
    # include .bashrc if it exists
    if [ -f "$HOME/.bashrc" ]; then
        . "$HOME/.bashrc"
    fi
fi

So it’s explicitly sourcing ~/.bashrc, so that both login and non-login interactive shells will all include the customizations added to that file.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0