Explain why .bash_logout won't run commands?

Question

So I've been wondering how to run these two lines of code everytime I close an open instance of Terminal:

history -c
cat /dev/null > ~/.bash_history

I export HISTFILE=5 on startup, but still want to flush that out when I'm done.

I've tried looking around a bit in a couple of places, and haven't had much luck.

I run Linux Mint, and would also note here that I ran into a similar issue with .bash_profile; eventually, I discovered I needed to place all start up code in .bashrc, so maybe that has something to do with it. Here's my .bash_logout file:

#!/bin/bash
# ~/.bash_logout: executed by bash(1) when login shell exits.

#this does nothing on exit...
echo 'logout'; sleep 2s

# when leaving the console clear the screen to increase privacy

if [ "$SHLVL" = 1 ]; then
    history -c
    cat /dev/null > ~/.bash_history
    [ -x /usr/bin/clear_console ] && /usr/bin/clear_console -q
fi

I've tried re-arranging this script many ways, I'm not sure if I don't understand how bash works, and if any of this is running in the first place. Does the fact that I run Xserver make bash consider Terminal something that isn't a log-out on exit?

It does say that I am not logged in, which would make sense:

$> shopt login_shell
login_shell     off

Answer 1

Assuming you’ve verified that it’s a login shell (shopt login_shell):

~/.bash_logout is only run if it you explicitly exit the shell with exit or logout, or by typing Control-D to enter an end-of-file at the command prompt. If you close the terminal emulator, processes are sent SIGHUP, and bash doesn’t run ~/.bash_logout in that case.

If you want to perform work any time bash exits (and whether it’s a login shell or not), use trap foo EXIT. The most convenient way to do this is to put your code in a shell function, e.g.,:

print_goodbye () { echo Goodbye; }
trap print_goodbye EXIT

Answer 2

~/.bash_logout is only run by a login shell (such as the one you get on tty sessions, or with bash -l). It is ignored by non-login shells, which most terminals run.

See the manual page of bash(1), under "INVOCATION", for further detail.

---

If you do not want to keep persistent history, just unset HISTFILE, or set HISTFILE=/dev/null. This will automatically discard history on exit, while still allowing it to be kept for the current shell (HISTSIZE=100).