Adjusting the volume on macOS with CLI

volume-ctl.sh

#!/bin/bash
# https://gist.github.com/kawaz/5aa9d792798ba49aace14d17b4e68b3e
set -eo pipefail

usage() {
    echo "Usage: $0 subcommand [args]"
    echo "  $0 get [output|input|alert|mute]    get volume settings"
    echo "  $0 set [output|input|alert] 0-100   set volume"
    echo "  $0 set mute [true|false]            set mute status"
    echo "  $0 help                             show this help"
    exit 1
}

case $1 in
get)
    if [[ -z $2 ]]; then
        if command -v jq >/dev/null; then
            osascript -e "get volume settings" | perl -pe's/\s*([\w\s]+):/"$1":/g;s/^/{/;s/$/}/' | jq .
        else
            osascript -e "get volume settings"
        fi
        exit
    fi
    case $2 in
    output | input | alert)
        osascript -e "get $2 volume of (get volume settings)"
        ;;
    mute)
        osascript -e "get output muted of (get volume settings)"
        ;;
    *)
        usage
        ;;
    esac
    ;;
set)
    case $2 in
    output | input | alert)
        osascript -e "set volume $2 volume $3"
        ;;
    mute)
        if [[ "$3" == "true" ]]; then
            osascript -e "set volume output muted true"
        elif [[ "$3" == "false" ]]; then
            osascript -e "set volume output muted false"
        else
            usage
        fi
        ;;
    esac
    ;;
*)
    usage
    ;;
esac