1.1.3 optparse: ヘルプメッセージを組み込んだパーザ

• portupgradeの例

  OptionParser.new(banner, COLUMNSIZE) do |opts|
  opts.def_option("-h", "--help",
        		    "Show this message") {
    print opts
    exit 0
  }
        
  opts.def_option("-a", "--all",
        		    "Do with all the installed packages") { |v|
    $all = v
    $recursive = false
    $upward_recursive = false
  }
        
  opts.def_option("-A", "--afterinstall=CMD",
        		    "Run the command after each installation") { |v|
    $afterinstall = v
    $afterinstall.strip!
  }
        
    :
        
  opts.def_tail_option '
        pkgname_glob is one of these: a full pkgname, a pkgname w/o version,
        a shell glob pattern in which you can use wildcards *, ?, and [..],
  an extended regular expression preceded by a colon (:), or a date range
  specification preceded by either < or >. See pkg_glob(1) for details.
        The package list is automatically sorted in dependency order.
        
        Environment Variables [default]:
  PACKAGES         packages directory [$PORTSDIR/packages]
  PKGTOOLS_CONF    configuration file [$PREFIX/etc/pkgtools.conf]
  PKG_BACKUP_DIR   directory for keeping old packages [$PKG_PATH]
  PKG_DBDIR        packages DB directory [/var/db/pkg]
  PKG_PATH         packages search path [$PACKAGES/All]
  PKG_TMPDIR       temporary directory for backup etc. [$TMPDIR]
  (Note: This must have enough free space when upgrading a big package)
  PORTSDIR         ports directory [/usr/ports]
  PORTS_DBDIR      ports db directory [$PORTSDIR]
  PORTS_INDEX      ports index file [$PORTSDIR/INDEX]
  PORTUPGRADE      default options (e.g. -v) [none]
  TMPDIR           temporary directory [/var/tmp]'