Linux Shell Scripting Cookbook - Third Edition

How to do it...

The watch command monitors the output of a command on the terminal at regular intervals. The syntax of the watch command is as follows:

    $ watch COMMAND

Consider this example:

    $ watch ls

Alternatively, it can be used like this:

    $ watch 'df /home'

Consider the following example:

    # list only directories
    $ watch 'ls -l | grep "^d"'

This command will update the output at a default interval of two seconds.

The -n SECONDS option defines the time interval for updating the output:

    # Monitor the output of ls -l every of 5 seconds
    $ watch -n 5 'ls -l'