Parameter expansion: is it possible to extract an internal substring?

General system Newbie
1

For example, how can I extract just leafpad out of

/usr/share/applications/leafpad.desktop

I would like to account for not just /usr/share/applications/ but also for ~/.local/share/applications.

The best I could come up with is to use a combination:
echo ${selected##*/} | cut -d '.' -f1 (where selected is in the context of the code below)

#!/usr/bin/bash

desktop_file() {
  fd . -H -e .desktop /usr/share/applications "$HOME/.local/share/applications"
}

selected="$(desktop_file | sort | fzf --reverse)"
[ -z "$selected" ] && exit
cd || return
echo ${selected##*/} | cut -d '.' -f1 |  tr '[:upper:]' '[:lower:]' | xargs -I{} setsid -f bash -c "{}"

Source: bits taken from here

(The tr bit is because of Alacritty.)

2 
basename /usr/share/applications/leafpad.desktop .desktop
3 
#!/usr/bin/env bash

MYPATH=/usr/share/applications/leafpad.desktop
NAME=$(basename ${MYPATH} .desktop)
echo "$NAME"
1 Like
4

This won’t remove the .desktop suffix if I’m right

5

You are right, I didn’t read it carefully enough. Fixed.

6

Maybe first we need to know exactly what the OP wants to do…

1 Like
7

I’ve given the entire script. It’s an application launcher with .desktop files as the source.

8

Do you want to extract the app name from the name of the desktop file, or from the contents of the desktop file?

9

Just from the name of the .desktop file, not from the contents.

10

OK, then basename is your command.

1 Like
11

Be aware that desktop files can also look like this:

okularApplication_powerpoint_calligra.desktop
org.strawberrymusicplayer.strawberry.desktop
12

Yes! I have /usr/share/applications/org.pwmt.zathura.desktop and that’s a problem.

So back to the drawing board :sweat_smile:!

13 
$ basename /usr/share/applications/org.pwmt.zathura.desktop .desktop
org.pwmt.zathura

Is this output not what you expect?

14

If you just want the name, I agree with @manual that extracting it out of the desktop file is a better solution.

15

deleted by author :blush:

16

Something like this:

cat /usr/share/applications/xed.desktop  | grep ^Exec= | head -n1 | cut -d'=' -f2 | awk '{print $1}'
1 Like
17

But even the above may not be optimal if there are many Exec= lines, or quotes used…

18

Yes, and there are the options like xed --new window and field codes (%F, %U, etc).

Overall too many possibilities :frowning:

19

The above already handles some problems, try it and see. :wink:

20

And I just saw there is
/usr/share/applications/org.gnome.FileRoller.desktop:TryExec=file-roller