How do I kill all screens?

You can use :

pkill screen

Or

killall screen

---

In OSX the process is called SCREEN in all caps. So, use:

pkill SCREEN

Or

killall SCREEN

If the screens are dead, use:

screen -wipe

Have recently begun to familiarize myself with awk I put together this and it served its purpose. I posted it since its quite easy to understand.

screen -ls | grep '(Detached)' | awk 'sys {screen -S $1 -X quit}'

Where screen -ls lists all current screens. grep 'pattern' filters out all matching rows. We can then get a handle for all detached screens and with awk sys {command} we can copy and paste together a command and execute it with sys, $1 refers to the first argument picked up by awk. Finally we execute the quit command with screen -X quit.