Understanding tee

The tee command is rather unique, because it’s not really a normal redirector. Rather, it’s a utility that can take output from a command and send it to both the screen and to a file at the same time. So, instead of using it with a redirector symbol as we’ve been doing, you’ll send it its input via a pipe.

If you need to see a command’s output on the screen and also save it as a text file, pipe the output of the command through the tee utility, like this:

[donnie@fedora ~]$ ps a | tee ps.txt
    PID TTY      STAT   TIME COMMAND
    972 tty1     Ss+    0:00 -bash
   1005 pts/0    Ss     0:00 -bash
   1076 pts/0    R+     0:00 ps a
   1077 pts/0    S+     0:00 tee ps.txt
[donnie@fedora ~]$ ls -l ps.txt
-rw-r--r--. 1 donnie donnie 181 Aug 12 17:29 ps.txt
[donnie@fedora ~]$

Note that you don’t have to use the stdout operator (>) with this command. The name of the text file is used as the argument for tee.

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