The keyboard shortcuts field in Unity works in a similar manner to .desktop files, i.e. commands are executed without any form of subshell or variable expansion and can't access any environment variables.

I wasn't able to find an official specification regarding the keyboard shortcuts menu but I think it's save to assume that command execution follows similar guidelines to the Exec field in XDG .desktop files.

What this means, in practice, is that there are two ways you can make your custom command-line work with the shortcuts menu:

1. Transform your commands into a simple shell script and point the keyboard shortcut to the shell script.

   
   
   

   For instance, you could paste the following into a new text file, name it something like custom_screenshot_script and make the script executable:

   
   
   

   #!/bin/bash
   
   gnome-screenshot --window --remove-border -f "~/Pictures/screenshot_$(date +%x_%H:%M:%S:%N).png"
   
   




2. Call bash to execute your command.

   
   
   

   This is more tricky because you have to escape your arguments correctly. Something like the following should work:

   
   
   

   bash -c "gnome-screenshot --window --remove-border -f "~/Pictures/screenshot_$(date +%x_%H:%M:%S:%N).png""