Required display service (X server) for Debian init script

Question

I'm on Debian 9.11 with the MATE desktop (pinebook pro)

I've an Init script /etc/init.d/customMapping that remaps some of my keys using both setxkbmap and xmodmap. Here it is

#! /bin/sh
BEGIN INIT INFO
Provides:          customMapping
Required-Start:    $local_fs x11-common xserver display
Required-Stop:     $local_fs x11-common xserver display
Default-Start:     2 3 4 5
Default-Stop:      0 1 6
Short-Description: Custom keyboard mapping
Description:       This is a simple Init script
Custom keyboard mapping
END INIT INFO

Some things that run always
echo "customMapping script"
Carry out specific functions when asked to by the system
case "$1" in
  start)
    echo "Starting script customMapping "
    echo "start" >> /opt/test.txt
# Make Caps Lock a Control key
setxkbmap -option ctrl:nocaps > /opt/logs 2>&1

# Swap Left Control with Left Alt
setxkbmap -option ctrl:swap_lalt_lctl > /opt/logs 2>&1

# Make Pause/Break an End key
xmodmap -e "keycode 127 = End" > /opt/logs 2>&1

# Make Screen Lock a Home key
xmodmap -e "keycode 78 = Home" > /opt/logs 2>&1

;;

stop)
    echo "Stopping custom Mapping"
    ;;
  *)
    echo "Usage: /etc/init.d/customMapping {start|stop}"
    exit 1
    ;;
esac
exit 0

As you can see I've tried several kind of keywords in the Required-Start section but this doesn't work and when I check in the /opt/logs file I see the following error messages

Cannot open display "default display"

Cannot open display "default display"

xmodmap: unable to open display ''

xmodmap: unable to open display ''

What value should I set in Required-Start in order for my script to access display (X server)? Also is the Default-Start values correct?

Thank you

Answer 1

You really don’t want to run these commands as a startup service, but rather something that is executed as part of your X session when it starts.

If they run in an init script, they run as root in the context of startup, not as part of your X session.

You’d be better off putting those commands in your xinitrc or xsessionrc (depending on how you launch X).