I just fired up my copy of 4.2 on simh....
4.2 BSD UNIX (myname)
login: root
Last login: Thu Sep 8 19:45:39 on console
4.2 BSD UNIX #3: Thu Sep 8 08:46:54 PDT 1983
Would you like to play a game?
You have mail.
Don't login as root, use su
myname# cd /bin
myname# ls bs
bs not found
myname# which bs
no bs in /etc /usr/ucb /bin /usr/bin /usr/local /usr/hosts .
myname# man bs
No manual entry for bs.
myname#
Sorry that wasn't much help.....