tee - read from standard input and write to standard output and files
tee [OPTION]... [FILE]...
Copy standard input to each FILE, and also to standard output.
If a FILE is -, copy again to standard output.
Written by Mike Parker, Richard M. Stallman, and David MacKenzie.
Report bugs to <bug-coreutils@gnu.org>.
Copyright (C) 2006 Free Software Foundation, Inc. This is free software. You may redistribute copies of it under the terms of the GNU General Public License <http://www.gnu.org/licenses/gpl.html>. There is NO WARRANTY, to the extent permitted by law.
The full documentation for tee is maintained as a Texinfo manual. If the info and tee programs are properly installed at your site, the command
info tee
should give you access to the complete manual.