Toggle OSx dock's mutability

dock_mut.rb

#!/usr/bin/env ruby

# get current state
immutable = `defaults read com.apple.dock contents-immutable`.to_i == 1

# toggle the state
immutable = !immutable

# write the state
`defaults write com.apple.dock contents-immutable -bool #{immutable ? "YES" : "NO"}`
`defaults write com.apple.dock size-immutable -bool #{immutable ? "YES" : "NO"}`

# kill the dock application
`killall Dock`