Question

Is it possible in Linux command line to have a command repeat every n seconds?

Say, I have an import running, and I am doing

ls -l

to check if the file size is increasing. I would like to have a command to have this repeat automatically.

Answer 1

Watch every 5 seconds …

watch -n 5 ls -l

If you wish to have visual confirmation of changes, append --differences prior to the ls command.

According to the OSX man page, there’s also

The –cumulative option makes highlighting “sticky”, presenting a
running display of all positions that have ever changed. The -t
or –no-title option turns off the header showing the interval,
command, and current time at the top of the display, as well as the
following blank line.

Linux/Unix man page can be found here