tac(1)
# Reverse output lines of file(s) and concatenate (reverse of cat).
tac FILE [FILE]
echo -e 'a1\nb2\nc3\nd4' | tac
# d4
# c3
# b2
# a1
# Reverse output lines of file(s) and concatenate (reverse of cat).
tac FILE [FILE]
echo -e 'a1\nb2\nc3\nd4' | tac
# d4
# c3
# b2
# a1