# File mk, line 632
def edit(file,linenum,err)
  if err
    puts "error in #{file}"
    puts "(Look in your bibliography file(s))}" if file =~ /\.bbl$/
    return true unless STDOUT.isatty
    x = nil
    while ( x = readline("\n=====> e(dit) q(uit) ") ) !~ /^(q|e)$/
        puts "you must type e or q"
    end
    return true if x == 'q'
  end
  linenum ||= 1
  edfile = file.empty? ? @edit : file
  File.exist?(edfile.chomp) or quit("Could not edit #{edfile}; vanished?",1)
  sys("#{ENV['EDITOR']} +#{linenum} #{edfile}",true)
  return false
end