Any way of auto starting Plank if you are not in Wayland?

Linux Discussion
1

So bash script options?

Query if Wayland is not running,
then start Plank at login.

Would probably use in a single command line in startup applications.

so if variable return confirms no wayland | PLANK

??

Any suggestions ?

2

This might help:

if [ "$XDG_SESSION_TYPE" = x11 ]; then
    echo "Yep.  X11"
else
    echo "Nope. Not X11"
fi
2 Likes
3

If i’d riff off MarkofCain, I’m using this one:

DisplayType=${DISPLAY:+X11}${WAYLAND_DISPLAY:+WAYLAND}
if [[ $DisplayType == 'X11' ]]; then
	echo "Yep.  X11"
else
	echo "Nope. Not X11"
fi
2 Likes
4

So if I wanted to reduce that to a single command to put in auto run of Gnome / KDE / Budgie

if [ “$XDG_SESSION_TYPE” = x11 ]; then &Plank

Should do it?

Or would I need to pipe the result using | ?

5

I just gave this a go on a Debian VM with my custom XFCE build and I ran into a few problems…

  • The XDG_SESSION_TYPE environment variable was set to tty because I started XFCE from tty (because i’m a weirdo) so the if statement wouldn’t work
  • If I ran plank by itself it errored which I fixed by passing it the variable during execution XDG_SESSION_TYPE=x11 plank

You also asked to only start plank if it wasn’t running so I added a pidof test.

This’d be the one-liner in POSIX:

[ "$XDG_SESSION_TYPE" = 'x11' ] && [ -z "$(pidof plank)" ] && plank &

If it doesn’t work for you (because of the forementioned), use this: (Wayland shouldn’t have a value for $DISPLAY)

[ -n "$DISPLAY" ] && [ -z "$(pidof plank)" ] && XDG_SESSION_TYPE=x11 plank &
1 Like
6

So Debian uses Dash in place of Bash don’t they?

What is the difference?
Is there anything that Bash will do that Dash won’t?

Just wondering if commands should be tested under both shell environments?

7

The following is my opinion within the limits of my understanding…

The two most common shell languages are POSIX script and BASH. BASH script needs to be run by bash (generally speaking) but POSIX script can be run in any shell that’s POSIX compliant. Fedora for example interprets POSIX script using bash where Debian as you pointed out uses dash.

Every *nix OS can run POSIX script and almost every *nix OS can run BASH. When you open a terminal or execute a script without a header, it’ll almost always be run in BASH unless #!/bin/sh or #!/bin/dash is at the top. Short answer is Debian has both.

As for speed and “better-ness”… this is where things get complicated…

dash is extremely fast but it’s also extremely limited as a language so you almost immediately have to lean on spinning up GNU tools and other programs to fill in the gaps if you want to get anything done. While these tools are often written in C and VERY fast compared to BASH… if you need to use subshells $() or do repeat quick operations it becomes extremely slow (sometimes by 10x to 20x by comparison) because of the overhead of having to launch the processes and interpretation of the arguments.

POSIX script can also make things harder to diagnose because it’s easy to end up in pipe hell and requires you know how to use a bunch of separate full featured programs all with their own unique quirks instead of one unified language of simple tools.

There’s a lot more to it… for example if you wanted the highest possible guarantee something with run everywhere then POSIX is the way to go but depending on what the script does it might require you add a ton of dependencies you wouldn’t need in BASH.

It’s good to use both and while most scripts run so fast it doesn’t mean anything to a human, sometimes there’s definitely a better one to use.

1 Like
8

Good summary, I think !

Not being an expert in these things of course

:grinning:

9

Dude! Ingenious method of testing for truth and only moving forward when the conditions are satisfied. My quest for knowledge is done for the day.