[lammps-users] How to Combine Shell Commands with Lammps Script

Hey all,
Any one familiar with using SHELL commands in input script ?
I read the documentation which gives one example of using Shell command in
the script. I am wondering what the rules I have to follow.
I am trying to run successive simulations of different settings(using different ensemble).
Hope somebody can help enlighten me !

If you read the doc page for the shell command, and tried it,
then what isn't clear or what didn't work as you expect?