I associated pdf with Okular using mimeopen. Then I became curious where it had saved the configuration. My first guess was:
but it didn't contain the right entry. So I searched:
updatedb && locate mime | xargs egrep -e "okular" 2> /dev/null
and found nothing. So which file is used mimeopen to save associations?
I started digging, following a clue from cas's comment, and I found a file:
with the content:
[Desktop Entry] Version=1.0 Encoding=UTF-8 Type=Application Name=okular NoDisplay=true Exec=okular
Which strangely does not have a MimeType record
My guess: Since I use openbox, which doesn't set $DE environmental variable mimeopen had been forced to create a new .desktop file when I used it. Which is inconvenient.
I read it is possible to run openbox inside other desktop environments. I will give it a try.