getopt_long_only - Linux

Overview

getopt_long_only is a versatile command-line option parsing utility that simplifies the processing of long options in shell scripts or C programs. It offers a powerful way to analyze user inputs and extract relevant information for custom commands.

Syntax

getopt_long_only [OPTIONS] [LONGOPTIONS] -- [ARGUMENT]...

Options/Flags

  • -q, –quiet: Suppresses error messages.
  • -v, –verbose: Prints all option processing messages.
  • -?, –help: Displays help message and exits.
  • –longoptions: Prints all specified long options and exits.

Examples

# Parse single-letter options
getopt_long_only "a:b:c" "abc:" -- "arg1" "arg2"

# Parse long options with optional arguments
getopt_long_only "--file=" "--exclude=" -- "input.txt" ".txt"

Common Issues

  • Missing argument: Ensure all options with arguments have the necessary values.
  • Ambiguous options: Avoid using short options that overlap with long options.
  • Invalid option: Use the --longoptions flag to verify valid options.

Integration

getopt_long_only can be used in shell scripts for advanced option parsing. For example:

#!/bin/bash

while getopt_long_only "n:f:" -- "$@" ; do
  case "$1" in
    -n) name="$2"; shift 2 ;;
    -f) file="$2"; shift 2 ;;
  esac
done

echo "Name: $name, File: $file"

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