# File rubygems/commands/signout_command.rb, line 19
def execute
  credentials_path = Gem.configuration.credentials_path
  if !File.exist?(credentials_path)
    alert_error 'You are not currently signed in.'
  elsif !File.writable?(credentials_path)
    alert_error "File '#{Gem.configuration.credentials_path}' is read-only."\
                ' Please make sure it is writable.'
  else
    Gem.configuration.unset_api_key!
    say 'You have successfully signed out from all sessions.'
  end
end