Open a file in the default text editor programmatically

Question

I'm writing a program and I need to implement opening a particular file in a text editor. The file type has a different association by default (it's associated to the program itself), so calling xdg-open $file wouldn't work. Using $EDITOR is sub-optimal because it usually contains the terminal text editor, and I'd like to open a GUI text editor if that's the first preference. It is also unclear how to find the default terminal emulator to open a terminal $EDITOR.

I can query the (possibly GUI) editor with xdg-mime query default text/plain, which gives me a .desktop file, but I'm not sure how to go about actually running it, especially since it may contain Terminal=true which then again raises an issue of figuring out what the default terminal is.

To clarify, the program is not a script or something which already runs in the terminal. It is a GUI application, so launching a terminal editor would require figuring out what the default terminal is.

So, what's the best way to programmatically open a file in a default, possibly GUI, text editor?

Answer 1

The *.desktop file you get by calling xdg-mime query default text/plain is in one of two locations:

$HOME/.local/share/applications/
/usr/share/applications/

So you need to look for it there, then parse the Exec= line and run it passing all the arguments, e.g.:

$(grep Exec /usr/share/applications/seahorse.desktop | cut -d= -f2) "$@"

To determine the default terminal emulator on debian-like distributions you can run the following and similarly parse the output to get the path:

update-alternatives --query x-terminal-emulator

or just try to run the command you need directly:

x-terminal-emulator -e "your command here"

If you need to make it distribution agnostic you'll need to implement Desktop Environment guessing as it seems to depend on the way each DE stores its configuration. You might want to take a look at xdg-terminal code which is part of xdg utilities package responsible for running the default terminal (but for some reason isn't distributed).