tac \- concatenate and print files in reverse
and writes it on the standard output, reversed by the file segments
specifies segments bounded on the left by
specifies right-bounded segments.
(print lines in reverse order).
From\ ' /usr/spool/mail/$USER
prints out one's mail messages, most recent first.
prints the file in reverse, line by line, and:
reverses each of the first two files by line and places the
concatenated result on the third.
cat(1), rev(1), tail(1), tmail(1)
doesn't yet handle multiple argument files exactly right. It's
also unclear which direction it should process them in.
does not (and cannot efficiently) work on piped input.