Try grep 'Path=' ~/.mozilla/firefox/profiles.ini | sed s/^Path=//. Default profile folder name is stored in profiles.ini. This will work fine while you've got single profile.

If you have more than one Firefox profile then the file format changes, so extracting the folder name becomes more tricky. Here's the script to do that:

#!/bin/bash



cd ~/.mozilla/firefox/

if [[ $(grep '[Profile[^0]]' profiles.ini) ]]

then PROFPATH=$(grep -E '^[Profile|^Path|^Default' profiles.ini | grep -1 '^Default=1' | grep '^Path' | cut -c6-)

else PROFPATH=$(grep 'Path=' profiles.ini | sed 's/^Path=//')

fi



echo $PROFPATH

This script will work in both cases, it selects the appropriate method depending on the amount of profiles. Works in OSX, too.