0.4 Conventions in This Book

ConstantWillison is used for HTTP headers, status codes, MIME content types, directives in configuration files, and computer output in text

Italic is used for filenames, pathnames, newsgroup names, Internet addresses (URLs), email addresses, variable names (except in examples), terms being introduced, commands, options/switches, program names, subroutine names, functions, arrays, operators, methods, and hostnames

ALL CAPS is used for environment variables, HTML attributes, and HTML tags (within angle brackets <>)