Making snap of a bash script

snapcraft
1

I’ve been trying to make my first snap. It’s just a bash script. I’ve followed the directions posted here but I keep facing the following error:

Failed to generate snap metadata: Specified command 'xst.sh' was not found.
Verify the command is correct and for a more deterministic outcome, specify the relative path to the command from the prime directory.

My snapcraft.yaml looks like the following:

name: xst
base: core18
version: '1.0'
summary: summary
description: | 
  Brief description

grade: devel
confinement: devmode
architectures: [ all ]

apps:
  xst:
    command: xst.sh

parts:
  xst:
    plugin: nil

Any help would be highly appreciated. Thanks.

2

First, make sure that xst.sh is set to executable. Second, you’re not copying it into your snap; your part is plugin: nil which means it won’t do anything. You likely want plugin: dump to copy the file(s) verbatim.

1 Like
3

Thanks a lot! That worked. I had another question. My script when run as a simple bash script like ./xst.sh takes three arguments. How can implement it in my snap so that it can be run like xst first_arg second_arg third_arg?

4

you don’t need to do anything special. it will take any commandline parameters as normal.

5

Okay thanks. My script has dependencies on some utilities of ImageMagick suit and some X11 tools. How do I meet these dependencies in my snap? I assume they need to go the parts template, but I have no idea how to implement them.

6

You need to look into stage-packages.

1 Like
7

Thanks. That helped a lot. But some commands inside my script are showing up as “not found” when I run the snap, for example

/snap/xst/x1/project/xst.sh: line 40: xprop: command not found

I’m not sure what package I need in order to make these commands available. Any advice?

8

Here’s how I usually find out which package a binary is in:

alan@mcp:~$ dpkg -S `which xprop`
x11-utils: /usr/bin/xprop
1 Like
9

I always forget about this and use apt-file instead, but of course that requires actually installing apt-file to begin with so your way is better :slight_smile:

1 Like
10

i’m also in the apt-file camp since you can search packages with it you do not have installed locally …

so just for reference:

$ sudo apt install apt-file
[...]
$ sudo apt-file update
[...]
$ apt-file search bin/xprop
x11-utils: /usr/bin/xprop
2 Likes
11

I’m having trouble locating packages for image and convert commands; they should be available since I’ve already included the ImageMagick as a dependency. :confused:

12

imagemagick uses /etc/alternatives:

$ ls -l $(which convert)
lrwxrwxrwx 1 root root 25 Aug 24  2014 /usr/bin/convert -> /etc/alternatives/convert
$ ls -l /etc/alternatives/convert
lrwxrwxrwx 1 root root 20 Jul 29  2016 /etc/alternatives/convert -> /usr/bin/convert-im6

snapcraft does not process alternatives so you must create a symlink (convert -> convert-im6) yourself or make your script directly call convert-im6