fan-control.sh

#!/usr/bin/env bash

set -e

minimum=2000
medium=4500
maximum=6200

value=$minimum

case "$1" in
    "min")
        value=$minimum
        ;;
    "med")
        value=$medium
        ;;
    "max")
        value=$maximum
        ;;
    *)
        value=$1
        ;;
esac

if [[ -z "$(echo $value | grep -P '^\d+$')" ]]
then
    echo 'Only numeric values can be specified'
    exit 1
fi

echo $value | sudo tee /sys/devices/platform/applesmc.768/fan1_min