Wall monitor power saving script (XRandR)

sleepscreens.sh

#!/usr/bin/env bash

set -euo pipefail
IFS=$'\n\t'

DISPLAY="${DISPLAY:-:0}"

turn_off_all_screens() {
    for MONITOR in $(xrandr -d :0 --listmonitors | awk '{print $4}'); do
        xrandr -d "$DISPLAY" --output "$MONITOR" --off
    done
}

turn_on_all_screens() {
    for MONITOR in $(xrandr -d :0 --listmonitors | awk '{print $4}'); do
        xrandr -d "$DISPLAY" --output "$MONITOR" --auto
    done
}

main() {
    if ! xrandr --help >/dev/null 2>&1; then
        echo "xrandr is not on the path; exiting..."
        exit 1
    fi

    if ! xrandr -d "$DISPLAY" --version >/dev/null 2>&1; then
        echo "xrandr does not appear to work with display $DISPLAY; exiting..."
        exit 1
    fi

    local WAKE_START_HOUR=8
    local WAKE_END_HOUR=18
    local SATURDAY=6

    local CURRENT_HOUR=$(date +"%k")
    local DAY_OF_WEEK=$(date +"%u")

    if [[ "$CURRENT_HOUR" -ge "$WAKE_START_HOUR" && "$CURRENT_HOUR" -lt "$WAKE_END_HOUR" && "$DAY_OF_WEEK" -lt "$SATURDAY" ]]; then
        turn_on_all_screens
    else
        turn_off_all_screens
    fi
}

main