How can I add a bash command to run while opening a file

Question

For example I have an image file that I open, is there a way to attach a bash command to run when I open that file? I have ruby script that I'd like to run when this file is accessed.

Thank you.

Why: For an experiment of mine, nothing hacky in my mind :)

Answer 1

The only method that springs to my mind is to change the default application for particular type of file to custom bash script:

1. First of all create a bashscript.sh that does two things: starts Your Ruby script and opens a file in "default" application, something like this:

   #!/bin/bash
   /path/to/Your/rubyscript.rb &
   /path/to/default/application "$1"
   

   Sign & and variable "$1" are crucial - & cause to not wait for execution of ruby script, "$1" is the name (and path) of Your file, so You have to pass them to "default" application. You may also pass them to Your ruby script. Make sure Your bash script is executable - sudo chmod +x bashscript.sh

2. Right click on Your file, select Open with ... -> Other application

3. Click on Use a custom command and type a path to bashscript.sh

4. Tick Set as default to make changes permanent

Now when You double-click on file with the same type Your ruby script should run and file should open in default application.