Prevent sleep when running scripts

Sometimes we need to execute commands that take some time to execute and normally you have your mac set up to sleep earlier than those scripts need to finish. Personally I don't like to mess with the sleep settings if what I need is temporary (just until the script is over). You can use Caffeine to do that, but I don't like to have several programs running and the need to install one more app just to make simple things. Furthermore, I need something to go back to normal (the sleep settings I had before) after the script is done.

So after some investigation, I found the pmset command really useful and the precise tool for my temporary scripts. In this case I use commands like:

pmset noidle & <command I need to run while preventing from sleep> ; killall pmset

Also, if I want to prevent sleep on a shell script that I'm coding, I find it better to use something like:

# prevent sleep (background running)
pmset noidle &
# save the process ID of pmset command
PMSETPID=$!

# now make everything you need here

# kill the pmset command running on background
kill $MPSETPID

Now I can go away from my Mac and it will run the command without interruptions and after it will save energy, like it normally does.