tee

Redirect output to multiple files, copies standard input to standard output and also to any files given as arguments. This is useful when you want not only to send some data down a pipe, but also to save a copy

SYNTAX
      tee [OPTION]... [FILE]...

OPTIONS

`-a'
`--append'
     Append standard input to the given files rather than overwriting
     them.

`-i'
`--ignore-interrupts'
     Ignore interrupt signals.

Example:

   ps -ax | tee processes.txt | more

If a file being written to does not already exist, it is created.
If a file being written to already exists, the data it previously contained is overwritten unless the `-a' option is used.

"Twenty years from now, you will be more disappointed by the things you didn't do than by the ones you did do. So throw off the bowlines, sail away from the safe harbour. Catch the trade winds in your sails. Explore. Dream. Discover." Mark Twain

Related commands:

echo - Display message on screen
head - Output the first part of file(s)
less - Display output one screen at a time
more - Display output one screen at a time
pg - Display one page at a time