MacOS Condition on Low Disk Space. Pass a number such as 90 as an argument, and if the exit code is 1, then a drive is over 90%.

IsDiskSpaceLow.sh

#!/usr/bin/env bash

# MacOS Condition on Low Disk Space. Pass a number such as 90 as an argument, and if the exit code is 1, then a drive is over 90%.
# This exludes any mounted dmg's, USB drives, or cdrom/dvd.

Percentage=$1
IsOver=$(df -H | grep -vE '^Filesystem|tmpfs|cdrom|loop|devfs|map| \/Volumes' | awk '{ print substr($5,1,length($5)-1) }' | awk -v p=$Percentage -F: '{if($1>p){print 1}else{print 0}}' | grep 1 | tail -n1)
exit "$IsOver"