Getoptstyle

Getoptstyle is a term used to describe a conventional approach to command-line option parsing that follows the patterns of the GNU getopt family. It is not a formal standard, but a widely used style for interpreting options and their arguments across languages and tools.

Key features: Options typically begin with a dash. Short options use a single letter and may be grouped (for example, -abc is equivalent to -a -b -c). Long options use two dashes (for example, --verbose). Options may require arguments, either as the next token (-f filename) or attached (-ffilename or --output=file). Some implementations allow optional arguments. Error handling commonly reports unknown options and missing arguments.

End of options: A double dash -- often marks the end of option parsing; subsequent tokens are treated as positional arguments.

Interoperability: In C and C++, the getopt and getopt_long functions implement this style. Scripting languages provide similar interfaces (Python’s getopt; libraries like argparse or optparse adopt similar semantics, with some differences).

Example: program -abc -f file --verbose --output=out.txt arg1.

Advantages and limitations: The style offers familiarity and compact syntax, but can be ambiguous for optional arguments and long-option synonyms, and may require careful handling of argument parsing edge cases.

History and usage: The style traces to early Unix tools and the GNU project, and remains a common baseline in CLI tool design. See also: getopt, getopt_long, POSIX, GNU, argparse, optparse.