[hacknews] tee -t

henry@utzoo.UUCP (Henry Spencer) (06/21/83)

Tee(1) has been modified so that it refuses to cooperate if both
input and output are tty's, unless the -t flag is given.  This is
a concession to the presence of both "ted" and "tee", which has
lead to disastrous typos on several occasions.  I also took the
opportunity to clean up tee's innards drastically.