Install
wget https://ftp.gnu.org/pub/gnu/global/global-6.6.12.tar.gzUnzip it tar -zxvf, Then Read INSTALL.
Usage
# gen DB
gtags -v
# update db
global -u
Ignore Some Dirs
cp /usr/local/share/gtags/gtags.conf ~/.globalrc
Edit β:skip=β, ref emacs - how gtags exclude some specific subdirectories - Stack Overflow