brew/Library/Homebrew/cmd/tap-unpin.rb

#:  * `tap-unpin` <tap>:
#:    Unpin <tap> so its formulae are no longer prioritized. See also `tap-pin`.

require "tap"

module Homebrew
  def tap_unpin
    ARGV.named.each do |name|
      tap = Tap.fetch(name)
      raise "unpinning #{tap} is not allowed" if tap.core_tap?
      tap.unpin
      ohai "Unpinned #{tap}"
    end
  end
end