touchid-enable-pam-sudo

#!/usr/bin/env ruby
# Source: https://github.com/MikeMcQuaid/dotfiles/blob/master/bin/touchid-enable-pam-sudo
# Enables sudo authentication using TouchID.

pam_sudo_filename = '/etc/pam.d/sudo'
pam_sudo_contents = File.read(pam_sudo_filename)
if pam_sudo_contents.include?('pam_tid.so')
  puts 'TouchID PAM sudo module already enabled!' unless ARGV.include?('--quiet')
  exit
end

first_line = '# sudo: auth account password session'
first_line_regex = /^#{first_line}$/
unless pam_sudo_contents.match?(first_line_regex)
  warn "Error: #{pam_sudo_filename} is not in the expected format!"
  abort
end

if Process.uid != 0
  puts "Rerunning #{$0} with sudo..."
  exec 'sudo', $0
end

pam_sudo_contents.sub!(
  first_line_regex,
  "#{first_line}\nauth       sufficient     pam_tid.so"
)

File.write(pam_sudo_filename, pam_sudo_contents)
puts 'TouchID PAM sudo module now enabled!'