grep -r "# TODO" .
I’ll give this a try before adding something to my .vimrc again.
Is also useful, as it prints the filename and the matching lines.
Edit: Nope, writes l̶i̶n̶e̶ ̶n̶u̶m̶b̶e̶r̶s̶ file names to output regardless. Boo.
option -h will disable filename in output