watch — stdin stdout - file -- opt --help --version
watch program executes
a given command at regular intervals; the default is every two
seconds. The command is passed to the shell (so be sure to quote or
escape any special characters), and the results are displayed in a
full-screen mode, so you can observe the output conveniently and see
what has changed. For example,
watch -n 60
date executes the
command once a minute, sort of a poor man’s clock. Type
^C to exit.
Set the time between executions, in seconds.
Highlight differences in the output, to emphasize what has changed from one execution to the next.