yes

YES(1)         BSD General Commands Manual        YES(1)

NAME
     yes -- be repetitively affirmative

SYNOPSIS
     yes [expletive]

DESCRIPTION
     yes outputs expletive, or, by default, ''y'', forever.

HISTORY
     The yes command appeared in 4.0BSD.

4th Berkeley Distribution        June 6, 1993

– Linux man page for command “yes”;
(compare a later version)