How do I force Gnome Commander to use VLC instead of Movie Player by default?
This feature is currently broken in GNOME Commander.
Since GNOME has changed to follow the freedesktop.org standard of handling mimetypes, the editing of preferred programs in GNOME Commander is currently broken (v 1.1.7). We do have this in our TODO file, but until GCMD can handle edititing of preferred programs, there are two other ways of managing this on user basis; use nautilus or manually edit the configuration files that controls mime types in your home directory. Using Nautilus for doing this can feel quite awkward for GNOME Commander users, we usually do not use GNOME Commander because we like using Nautilus." - GNOME Commander
Here is how to do it manually: https://gcmd.github.io/doc.html#mime
I am using ubuntu 13.10
Editing file ~/.local/share/applications/defaults.list or ~/.local/share/applications/mimeapps.list does not work for Gnome Commander. The file you need to edit is located at /etc/gnome/defaults.list