ngrep(8) on Linux
The text fae585a2efa5, as Debian 3.1 (Sarge) shipped it.
network grep
Flags it lists
-
-A -
-D -
-F -
-I -
-O -
-P -
-R -
-S -
-T -
-V -
-W -
-X -
-c -
-d -
-e -
-h -
-i -
-l -
-n -
-p -
-q -
-s -
-t -
-v -
-w -
-x