How can I prevent idle sleep in a long-running bash script on Mac OS?

Question

I have a bash script that executes several long-running commands on Mac OS. How can I prevent the computer from going to sleep while the script is running?

Answer 1

I found that I can achieve the desired behavior by adding this line to the start of the script:

caffeinate -i -w $$ &

How it works:

• caffeinate is a built-in Mac OS utility for creating power management assertions to prevent sleep.
  • The -i flag tells caffeinate to prevent idle sleep.
  • The -w flag tells caffeinate to wait until the specified process finishes.
  • $$ is a shell variable containing the current PID. Together with the -w flag this tells caffeinate to prevent sleep for the duration of the shell script.
• The final & runs the command in the background so the script can continue running.