Running script as root at startup Ubuntu 19.04

[mysticduck]

I needed to run

modprobe -r lp

at startup so Virtualbox could grab the parallel port. I made a script "unload lp.sh" with the above code, ran chmod u+x on it to make it executable, put it into startup applications and restarted, no joy. After some searching I tried adding

#!/bin/bash

to the beginning of the script, also no joy, but if I ran the script from terminal it worked as expected. I fixed my issue by creating /etc/rc.local and putting the modprobe in there, but I'm curious why it didn't work through startup applications. This is purely for my edification, I like knowing how and why stuff does (or doesn't) work.



Thanks!

[sisco311]

Add `lp' to the /etc/modules file.
https://help.ubuntu.com/community/Loadable_Modules

EDIT: Oh, you have to remove the module. You can blacklist it in /etc/modprobe.d/blacklist:

blacklist lp

[mysticduck]

That info was what I was looking for before I started making the script, thanks! I am however still curious why my method didn't work, more for future reference than anything else.

[sisco311]

"startup applications" are automatically launched during startup of the user's desktop environment after the user has logged in, but modprobe must be run as root.
See: https://specifications.freedesktop.o...ec-latest.html

Putting the command in /etc/rc.local should be avoided. The file is executed by systemd for backward compatibility with sysvinit but you can't predict at which point of the booting process is executed.

[mysticduck]

Gotcha, I was under the assumption startup applications were run as root. I'll do the blacklist like you mentioned, thanks for all the help and information!