Flowdock

The GetoptLong class allows you to parse command line options similarly to the GNU getopt_long() C library call. Note, however, that GetoptLong is a pure Ruby implementation.

GetoptLong allows for POSIX-style options like --file as well as single letter options like -f

The empty option -- (two minus symbols) is used to end option processing. This can be particularly important if options have optional arguments.

Here is a simple example of usage:

require 'getoptlong'
require 'rdoc/usage'

opts = GetoptLong.new(
  [ '--help', '-h', GetoptLong::NO_ARGUMENT ],
  [ '--repeat', '-n', GetoptLong::REQUIRED_ARGUMENT ],
  [ '--name', GetoptLong::OPTIONAL_ARGUMENT ]
)

dir = nil
name = nil
repetitions = 1
opts.each do |opt, arg|
  case opt
    when '--help'
      puts <<-EOF
hello [OPTION] ... DIR

-h, --help:
   show help

--repeat x, -n x:
   repeat x times

--name [name]:
   greet user by name, if name not supplied default is John

DIR: The directory in which to issue the greeting.
      EOF
    when '--repeat'
      repetitions = arg.to_i
    when '--name'
      if arg == ''
        name = 'John'
      else
        name = arg
      end
  end
end

if ARGV.length != 1
  puts "Missing dir argument (try --help)"
  exit 0
end

dir = ARGV.shift

Dir.chdir(dir)
for i in (1..repetitions)
  print "Hello"
  if name
    print ", #{name}"
  end
  puts
end

Example command line:

hello -n 6 --name -- /tmp

Constants

ORDERINGS = [REQUIRE_ORDER = 0, PERMUTE = 1, RETURN_IN_ORDER = 2]

ARGUMENT_FLAGS = [NO_ARGUMENT = 0, REQUIRED_ARGUMENT = 1, OPTIONAL_ARGUMENT = 2]

STATUS_TERMINATED = 0, 1, 2

Attributes

[R] ordering

Return ordering.

[W] quiet

Set/Unset `quiet’ mode.

[R] quiet

Return the flag of `quiet’ mode.

[W] quiet?

Set/Unset `quiet’ mode.

[R] error

Examine whether an option processing is failed.

[R] error?

Examine whether an option processing is failed.

Show files where this class is defined (1 file)
Register or log in to add new notes.