tee(1) on Linux
The text c4c3e082d4c3, as Debian 2.1 (Slink), Debian 2.0 (Hamm), Debian 1.3 (Bo) shipped it.
read from standard input and write to standard output and files
Flags it lists
-
--append -
--help -
--ignore-interrupts -
--version -
-a -
-i