Uninstalling

Delete the session data storage directory

% rm -rf $ABBR_TMPDIR

If you want to delete the user abbreviations file,

% rm $ABBR_USER_ABBREVIATIONS_FILE

If you haven't customized $ABBR_USER_ABBREVIATIONS_FILE, you will probably want to delete its parent directory

# check whether there's anything in there
% ls $ABBR_USER_ABBREVIATIONS_FILE:h
# IF you want to delete it
% rm -rf $ABBR_USER_ABBREVIATIONS_FILE:h

Then follow the standard uninstall procedure for your installation method. This is typically the reverse of what you did to install.