In Rawpedia page about Preferences/General Tab/External Editor, it is written:
Linux
If you use Linux, the GIMP option is hard-coded to look for the GIMP executable gimp anywhere.
For the command line option, simply write the full path including
the executable. You may need to enclose the whole line in parenthesis if
you need to pass arguments, see the example. Environment variables such
as ~ or $HOME are not supported.
Examples:
“/usr/bin/geeqie --remote”
The above command opens the image in a single instance of Geeqie.
Note that you need to enclose it in parentheses because you’re passing
the “–remote” option.
It is not clear because I can see no parenthesis
Thanks