Wait, wait!!

After years of shell scripting I wasn't aware of the useful "wait" command. It makes the parent process wait until all child processes finish. I mean:

  #!/bin/sh
  
  (sleep  5; echo "good bye from child 1") &
  (sleep 10; echo "good bye from child 2") &
  
  wait
  echo "good bye from parent process"

When executed, this script will output:

  good bye from child 1
  good bye from child 2
  good bye from parent process

Arggg, so many lost hours writing custom code to do what was only one line away.