The file command
can be used on a Linux
system to determine what type of data a file holds, e.g.,
file Untitled.png. You can determine the
media type, aka
MIME type, by using
the --mime-type option for the file command. E.g.,
file --mime-type Untitled.png. You can determine which application
is the default application for opening files of that
file type using the
xdg-mime
command — the
xdg-mime program is a command line tool that can be used to determine
what application handles a particular file type. E.g., xdg-mime
query default image/png — you need to specify the filetype
in the "minor/major" format that xdg-mime expects, which is what you see
in the output of the file --mime-type command.
$ file Documents/Untitled.png Documents/Untitled.png: PNG image data, 597 x 113, 8-bit/color RGBA, non-interlaced $ file --mime-type Documents/Untitled.png Documents/Untitled.png: image/png $ xdg-mime query default image/png org.gnome.Loupe.desktop $ file --mime-type Documents/Cocoa-Lead.odt Documents/Cocoa-Lead.odt: application/vnd.oasis.opendocument.text $ xdg-mime query default application/vnd.oasis.opendocument.text libreoffice-writer.desktop $
The default file
manager for Ubuntu
Linux is GNOME Files.
You can make another application the default file manager, if you like.
Some alternatives are
Thunar,
Nemo,
Krusader, or
Dolphin.
You can determine which application is the default file manager with the
command xdg-mime query default inode/directory. You can set
the default file manager with the command xdg-mime default
fmgr.desktop where fmgr is the filemanager you wish to
use.
$ xdg-mime default nemo.desktop inode/directory $ xdg-mime query default inode/directory nemo.desktop $ xdg-mime default thunar.desktop inode/directory $ xdg-mime query default inode/directory thunar.desktop $
You can also find or update the default file manager by checking or
updating the ~/.config/mimeapps.list file.
$ grep inode/directory ~/.config/mimeapps.list
inode/directory=thunar.desktop
$You can also check on which app is currently managing the desktop/file
browser using the
ps command. E.g., if I
wanted to check on whether any of Nautilus, Thunar, or Dolphin were running I
could use the command ps aux | grep -E 'nautilus|thunar|dolphin|nemo'
| grep -v 'grep'. You can check on whether a specific file manager,
such as Thunar is running using the
pgrep command, e.g.,
pgrep -a thunar.
$ ps aux | grep -E 'nautilus|thunar|dolphin|nemo' | grep -v 'grep' lisa@ad+ 35812 0.5 0.5 4234520 691816 ? Sl May22 299:39 /usr/bin/nautilus --gapplication-service lisa@ad+ 1214435 0.1 0.4 4906068 560264 ? Sl Jun12 30:07 /usr/bin/thunar $ grep -l "inode/directory" /usr/share/applications/*.desktop /usr/share/applications/nemo.desktop /usr/share/applications/org.gnome.baobab.desktop /usr/share/applications/org.gnome.Nautilus.desktop /usr/share/applications/org.kde.krusader.desktop /usr/share/applications/thunar.desktop $ pgrep -a thunar 1214435 /usr/bin/thunar $
If you wish to use a different file manager than the default one, you
will need to first install that file manager, which you can do from a
terminal window using a sudo apt install command, e.g.,
sudo apt install nemo or sudo apt install thunar.
You can see which file manager applications are available with the
command grep -l "inode/directory" /usr/share/applications/*.desktop
command.
$ grep -l "inode/directory" /usr/share/applications/*.desktop /usr/share/applications/nemo.desktop /usr/share/applications/org.gnome.baobab.desktop /usr/share/applications/org.gnome.Nautilus.desktop /usr/share/applications/org.kde.krusader.desktop /usr/share/applications/thunar.desktop $
You can open the default file manager and have it display the files
in the current working directory by issuing the command xdg-open .
in that directory. Or you can specify the directory, e.g.,
xdg-open $HOME.
References:
Related: