Documented in Volume 1 of the UNIX Programmers Manual.
% tail filename
will list the last ten lines of filename.
% tail +95 100linefile
-and-
% tail -5 100linefile
are equivalent and list the last five lines of a hundred line file.
% tail -r filename
lists the file backwards.
BUGS:
1) the man page for tail states that the entire file will be listed;
in fact, tail stops after listing only about 128 lines. If the file
you want to list in reverse order is longer than 128 lines, try:
% cat -n filename | sort -nr | sed "s/^.......//"
-or-
% ( echo 'g/^/m0' ; echo '%p' ) | ex filename
2) tail will process only the first file named as an argument.
Flags l, b, and c specify counting by lines, blocks, or characters.
Flag f will continue to read in hopes the file will grow.