Define default applications on the command-line

The xdg-mime command, which is part of the xdg-utils package, can be used to define default application associations via the XDG MIME Applications specification.

https://wiki.archlinux.org/title/Default_applications https://wiki.archlinux.org/title/XDG_MIME_Applications

• Query the MIME type of a file:

  xdg-mime query filetype <path-to-file>
  

• Display the default application for PDFs:

  xdg-mime query default application/pdf
  

• Find the desktop entry name of Firefox:

  ls -l /usr/share/applications | grep -i firefox
  

• Set Firefox as the default application for html files:

  xdg-mime default firefox.desktop text/html