Subject: bug#67680: nohup is not giving immunity to SIGHUP

From: Bob Hepple <[email-masked]>
Date: Thu, 7 Dec 2023 18:13:01 +1000

$ nohup --version
nohup (GNU coreutils) 9.3
$ uname -a
Linux achar-void 6.5.12_1 #1 SMP PREEMPT_DYNAMIC Mon Nov 20 18:31:50
UTC 2023 x86_64 GNU/Linux

This is on void, but it also behaves the same on fedora-38

I have extracted a minimal example - it looks like a stupid thing to
do but it demonstrates the problem. A full and non-stupid script is at

https://gitlab.com/wef/dotfiles/-/blob/master/bin/fzf-launcher

Nevertheless - the following commands are run from bash in a graphical
session. 'foot' is a terminal emulator - any terminal emulator can be
used - I have tried mrxvt, urxvt, alacritty.

'imv' is a simple program that opens a window. Anything else with a
.desktop file could be used, such as 'rofi' or 'xsane'.

$ foot -e bash -c "nohup gtk-launch imv &"
... fails - the program imv briefly opens a window and immediately closes

$ foot -e bash -c "nohup gtk-launch imv & sleep 3"
.... the 'imv' window shows but it is closed after 3 seconds - clearly
the program 'imv' starts but is killed by something when the script
terminates.

$ foot -e bash -c "trap '' HUP; nohup gtk-launch imv &"
... works perfectly - the 'something' that is killing imv is
apparently the HUP signal! So why does nohup not grant immunity to
HUP?