GNU Global

Install

wget https://ftp.gnu.org/pub/gnu/global/global-6.6.12.tar.gz

Unzip 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 ":skip=", ref emacs - how gtags exclude some specific subdirectories - Stack Overflow