Programming Perl, 4th Edition

User Efficiency

Making other people’s lives easier is a lot more work than making stuff easy for you.

• Instead of making users enter data line by line, pop users into their favorite editor.

• Better yet, use a GUI like the Perl /Tk or Wx modules, where users can control the order of events.

• Put up something for users to read while you continue doing work.

• Use autoloading so that the program appears to run faster.

• Give the option of helpful messages at every prompt.

• Give a helpful usage message if users don’t give correct input.

• Include extended examples in the documentation, and complete example programs in the distribution.

• Display the default action at every prompt, and maybe a few alternatives.

• Choose defaults for beginners. Allow experts to change the defaults.

• Use single-character input where it makes sense.

• Pattern the interaction after other things the user is familiar with.

• Make error messages clear about what needs fixing. Include all pertinent information such as filename and error code, like this:

  open(FILE, $file) || die "$0: Can’t open $file for reading: $!\n";

• Use fork && exit to detach from the terminal when the rest of the script is just batch processing.

• Allow arguments to come from either the command line or standard input.

• Use configuration files with a simple text format. There are many modules for this already on CPAN.

• Don’t put arbitrary limitations into your program.

• Prefer variable-length fields over fixed-length fields.

• Use text-oriented network protocols.

• Tell everyone else to ...