How can I check which application opens a file by extension?

Question

I am on a debian 9 system with unknown desktop environment (ssh access). How can I find out which program is used by default to view a file with a given extension (e.g. pdf)?

Edit: Since extension is not important to the decision, the mime type of the given file can be found by using file

file -i file.ext

Extensions mean nothing in Linux, just to us humans. The magic bits of a file though.... — ivanivan, Nov 02 '17 at 13:39

score 8 · Accepted Answer · answered Nov 02 '17 at 13:38

8

Ask xdg-mime.

$ xdg-mime query default application/pdf
atril.desktop

answered Nov 02 '17 at 13:38

Ignacio Vazquez-Abrams

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Is that desktop agnostic? – glenn jackman Nov 02 '17 at 14:16
2

It's desktop-agnostic as long as the desktop follows the [XDG specifications](https://www.freedesktop.org/wiki/Specifications/). – Ignacio Vazquez-Abrams Nov 02 '17 at 14:18
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If you are unsure which filetype, you can use `xdg-mime query filetype path/to/file`. – Nov 02 '17 at 15:50

How can I check which application opens a file by extension?

1 Answers1