Recreating OS X media keys on the command line

Place this at ~/mediakeys.scpt (download):

on run argv
    if (count of argv) is greater than 0 then
        set theCommand to item 1 of argv
    else
        set theCommand to ""
    end if
    
    set systemVolume to (output volume of (get volume settings))
    
    if theCommand is equal to "-" then
        set volume output volume systemVolume - 5
    else if theCommand is equal to "--" then
        set volume output volume systemVolume - 10
    else if theCommand is equal to "+" then
        set volume output volume systemVolume + 5
    else if theCommand is equal to "++" then
        set volume output volume systemVolume + 10
    else if theCommand is equal to "mute" then
        set volume output volume 0
    else if theCommand is equal to "unmute" then
        set volume output volume 45
        
    else if appIsRunning("Rdio") then
        tell application "System Events"
            if theCommand is equal to "n" or theCommand is equal to "next" then
                tell application "Rdio" to next track
            else if theCommand is equal to "p" or theCommand is equal to "previous" then
                tell application "Rdio" to previous track
            else
                tell application "Rdio" to playpause
            end if
        end tell
        
    else if appIsRunning("iTunes") then
        tell application "System Events"
            if theCommand is equal to "n" or theCommand is equal to "next" then
                tell application "iTunes" to next track
            else if theCommand is equal to "p" or theCommand is equal to "previous" then
                tell application "iTunes" to previous track
            else
                tell application "iTunes" to playpause
            end if
        end tell
    else
        beep
    end if
end run

on appIsRunning(appName)
    tell application "System Events" to (name of processes) contains appName
end appIsRunning

…and alias it:

alias m="osascript ~/mediakeys.scpt"

Supports iTunes and Rdio, whichever is open. Available commands:

• m to play or pause
• m n or m next for next track
• m p or m previous for previous
• m + / m ++ to increase system volume by 5 or 10%
• m - / m -- to decrease