xdg-mime

Query and manage MIME types according to the XDG standard. More information: https://portland.freedesktop.org/doc/xdg-mime.html.

Display the MIME type of a file:

xdg-mime query filetype {{path/to/file}}

Display the default application for opening PNGs:

xdg-mime query default {{image/png}}

Display the default application for opening a specific file:

xdg-mime query default $(xdg-mime query filetype {{path/to/file}})

Set imv as the default application for opening PNG and JPEG images:

xdg-mime default {{imv.desktop}} {{image/png}} {{image/jpeg}}