> > For accuracy, under POSIX, `grep` indeed is required to always print whole lines, however GNU `grep` has...
-o, --only-matching Print only the matched (non-empty) parts of a matching line, with each such part on a separate output line. ...and BSD `grep` has... -o, --only-matching Prints only the matching part of the lines. GNU and BSD `grep` are common on newer distros; the POSIX (not to use '-o') specification is useful for portability and older installations. ~ $ echo foo | grep -o o o o ~ $ grep --version grep (GNU grep) 3.12 Wiley On Tue, 20 May 2025 16:20:46 -0400, Greg Wooledge wrote: > > grep always prints whole lines. It doesn't just print the matching part > > of a line.