OptionParser is a class for command-line option analysis. It is much more advanced, yet also easier to use, than GetoptLong, and is a more Ruby-oriented solution.
The argument specification and the code to handle it are written in the same place.
It can output an option summary; you don't need to maintain this string separately.
Optional and mandatory arguments are specified very gracefully.
Arguments can be automatically converted to a specified class.
Arguments can be restricted to a certain set.
All of these features are demonstrated in the examples below. See make_switch for full documentation.
require 'optparse' options = {} OptionParser.new do |opts| opts.banner = "Usage: example.rb [options]" opts.on("-v", "--[no-]verbose", "Run verbosely") do |v| options[:verbose] = v end end.parse! p options p ARGV
OptionParser can be used to automatically generate help for the commands you write:
require 'optparse' Options = Struct.new(:name) class Parser def self.parse(options) args = Options.new("world") opt_parser = OptionParser.new do |opts| opts.banner = "Usage: example.rb [options]" opts.on("-nNAME", "--name=NAME", "Name to say hello to") do |n| args.name = n end opts.on("-h", "--help", "Prints this help") do puts opts exit end end opt_parser.parse!(options) return args end end options = Parser.parse %w[--help] #=> # Usage: example.rb [options] # -n, --name=NAME Name to say hello to # -h, --help Prints this help
For options that require an argument, option specification strings may include an option name in all caps. If an option is used without the required argument, an exception will be raised.
require 'optparse' options = {} OptionParser.new do |parser| parser.on("-r", "--require LIBRARY", "Require the LIBRARY before executing your script") do |lib| puts "You required #{lib}!" end end.parse!
Used:
bash-3.2$ ruby optparse-test.rb -r optparse-test.rb:9:in `<main>': missing argument: -r (OptionParser::MissingArgument) bash-3.2$ ruby optparse-test.rb -r my-library You required my-library!
OptionParser supports the ability to coerce command line arguments into objects for us.
OptionParser comes with a few ready-to-use kinds of type coercion. They are:
Date – Anything accepted by Date.parse
DateTime – Anything accepted by DateTime.parse
Time – Anything accepted by Time.httpdate
or
Time.parse
URI – Anything accepted by URI.parse
Shellwords – Anything accepted by Shellwords.shellwords
String – Any non-empty string
Integer – Any integer. Will convert octal. (e.g. 124, -3, 040)
Float – Any float. (e.g. 10, 3.14, -100E+13)
Numeric – Any integer, float, or rational (1, 3.4, 1/3)
DecimalInteger – Like
Integer
, but no octal format.
OctalInteger – Like
Integer
, but no decimal format.
DecimalNumeric – Decimal integer or float.
TrueClass – Accepts '+, yes, true, -, no, false' and defaults as
true
FalseClass – Same as TrueClass
, but defaults to
false
Array – Strings separated by ',' (e.g. 1,2,3)
Regexp – Regular expressions. Also includes options.
We can also add our own coercions, which we will cover soon.
As an example, the built-in Time
conversion is used. The other
built-in conversions behave in the same way. OptionParser will attempt to parse the
argument as a Time
. If it succeeds, that time will be passed
to the handler block. Otherwise, an exception will be raised.
require 'optparse' require 'optparse/time' OptionParser.new do |parser| parser.on("-t", "--time [TIME]", Time, "Begin execution at given time") do |time| p time end end.parse!
Used:
bash-3.2$ ruby optparse-test.rb -t nonsense ... invalid argument: -t nonsense (OptionParser::InvalidArgument) from ... time.rb:5:in `block in <top (required)>' from optparse-test.rb:31:in `<main>' bash-3.2$ ruby optparse-test.rb -t 10-11-12 2010-11-12 00:00:00 -0500 bash-3.2$ ruby optparse-test.rb -t 9:30 2014-08-13 09:30:00 -0400
The accept
method on OptionParser may be used to create converters.
It specifies which conversion block to call whenever a class is specified.
The example below uses it to fetch a User
object before the
on
handler receives it.
require 'optparse' User = Struct.new(:id, :name) def find_user id not_found = ->{ raise "No User Found for id #{id}" } [ User.new(1, "Sam"), User.new(2, "Gandalf") ].find(not_found) do |u| u.id == id end end op = OptionParser.new op.accept(User) do |user_id| find_user user_id.to_i end op.on("--user ID", User) do |user| puts user end op.parse!
output:
bash-3.2$ ruby optparse-test.rb --user 1 #<struct User id=1, name="Sam"> bash-3.2$ ruby optparse-test.rb --user 2 #<struct User id=2, name="Gandalf"> bash-3.2$ ruby optparse-test.rb --user 3 optparse-test.rb:15:in `block in find_user': No User Found for id 3 (RuntimeError)
The following example is a complete Ruby program. You can run it and see
the effect of specifying various options. This is probably the best way to
learn the features of optparse
.
require 'optparse' require 'optparse/time' require 'ostruct' require 'pp' class OptparseExample Version = '1.0.0' CODES = %w[iso-2022-jp shift_jis euc-jp utf8 binary] CODE_ALIASES = { "jis" => "iso-2022-jp", "sjis" => "shift_jis" } class ScriptOptions attr_accessor :library, :inplace, :encoding, :transfer_type, :verbose, :extension, :delay, :time, :record_separator, :list def initialize self.library = [] self.inplace = false self.encoding = "utf8" self.transfer_type = :auto self.verbose = false end def define_options(parser) parser.banner = "Usage: example.rb [options]" parser.separator "" parser.separator "Specific options:" # add additional options perform_inplace_option(parser) delay_execution_option(parser) execute_at_time_option(parser) specify_record_separator_option(parser) list_example_option(parser) specify_encoding_option(parser) optional_option_argument_with_keyword_completion_option(parser) boolean_verbose_option(parser) parser.separator "" parser.separator "Common options:" # No argument, shows at tail. This will print an options summary. # Try it and see! parser.on_tail("-h", "--help", "Show this message") do puts parser exit end # Another typical switch to print the version. parser.on_tail("--version", "Show version") do puts Version exit end end def perform_inplace_option(parser) # Specifies an optional option argument parser.on("-i", "--inplace [EXTENSION]", "Edit ARGV files in place", "(make backup if EXTENSION supplied)") do |ext| self.inplace = true self.extension = ext || '' self.extension.sub!(/\A\.?(?=.)/, ".") # Ensure extension begins with dot. end end def delay_execution_option(parser) # Cast 'delay' argument to a Float. parser.on("--delay N", Float, "Delay N seconds before executing") do |n| self.delay = n end end def execute_at_time_option(parser) # Cast 'time' argument to a Time object. parser.on("-t", "--time [TIME]", Time, "Begin execution at given time") do |time| self.time = time end end def specify_record_separator_option(parser) # Cast to octal integer. parser.on("-F", "--irs [OCTAL]", OptionParser::OctalInteger, "Specify record separator (default \\0)") do |rs| self.record_separator = rs end end def list_example_option(parser) # List of arguments. parser.on("--list x,y,z", Array, "Example 'list' of arguments") do |list| self.list = list end end def specify_encoding_option(parser) # Keyword completion. We are specifying a specific set of arguments (CODES # and CODE_ALIASES - notice the latter is a Hash), and the user may provide # the shortest unambiguous text. code_list = (CODE_ALIASES.keys + CODES).join(', ') parser.on("--code CODE", CODES, CODE_ALIASES, "Select encoding", "(#{code_list})") do |encoding| self.encoding = encoding end end def optional_option_argument_with_keyword_completion_option(parser) # Optional '--type' option argument with keyword completion. parser.on("--type [TYPE]", [:text, :binary, :auto], "Select transfer type (text, binary, auto)") do |t| self.transfer_type = t end end def boolean_verbose_option(parser) # Boolean switch. parser.on("-v", "--[no-]verbose", "Run verbosely") do |v| self.verbose = v end end end # # Return a structure describing the options. # def parse(args) # The options specified on the command line will be collected in # *options*. @options = ScriptOptions.new @args = OptionParser.new do |parser| @options.define_options(parser) parser.parse!(args) end @options end attr_reader :parser, :options end # class OptparseExample example = OptparseExample.new options = example.parse(ARGV) pp options # example.options pp ARGV
For modern shells (e.g. bash, zsh, etc.), you can use shell completion for command line options.
The above examples should be enough to learn how to use this class. If you have any questions, file a ticket at bugs.ruby-lang.org.
Decimal integer format, to be converted to Integer.
Decimal integer/float number format, to be converted to Integer for integer format, Float for float format.
Ruby/C like octal/hexadecimal/binary integer format, to be converted to Integer.
See accept.
# File optparse.rb, line 1098 def self.accept(*args, &blk) top.accept(*args, &blk) end
# File optparse/version.rb, line 49 def each_const(path, base = ::Object) path.split(/::|\//).inject(base) do |klass, name| raise NameError, path unless Module === klass klass.constants.grep(/#{name}/i) do |c| klass.const_defined?(c) or next klass.const_get(c) end end end
See getopts.
# File optparse.rb, line 1696 def self.getopts(*args) new.getopts(*args) end
Returns an incremented value of default
according to
arg
.
# File optparse.rb, line 1034 def self.inc(arg, default = nil) case arg when Integer arg.nonzero? when nil default.to_i + 1 end end
Initializes the instance and yields itself if called with a block.
banner
Banner message.
width
Summary width.
indent
Summary indent.
# File optparse.rb, line 1053 def initialize(banner = nil, width = 32, indent = ' ' * 4) @stack = [DefaultList, List.new, List.new] @program_name = nil @banner = banner @summary_width = width @summary_indent = indent @default_argv = ARGV add_officious yield self if block_given? end
See reject.
# File optparse.rb, line 1111 def self.reject(*args, &blk) top.reject(*args, &blk) end
# File optparse/version.rb, line 59 def search_const(klass, name) klasses = [klass] while klass = klasses.shift klass.constants.each do |cname| klass.const_defined?(cname) or next const = klass.const_get(cname) yield klass, cname, const if name === cname klasses << const if Module === const and const != ::Object end end end
# File optparse/version.rb, line 4 def show_version(*pkgs) progname = ARGV.options.program_name result = false show = proc do |klass, cname, version| str = "#{progname}" unless klass == ::Object and cname == :VERSION version = version.join(".") if Array === version str << ": #{klass}" unless klass == Object str << " version #{version}" end [:Release, :RELEASE].find do |rel| if klass.const_defined?(rel) str << " (#{klass.const_get(rel)})" end end puts str result = true end if pkgs.size == 1 and pkgs[0] == "all" self.search_const(::Object, /\AV(?:ERSION|ersion)\z/) do |klass, cname, version| unless cname[1] == ?e and klass.const_defined?(:Version) show.call(klass, cname.intern, version) end end else pkgs.each do |pkg| begin pkg = pkg.split(/::|\//).inject(::Object) {|m, c| m.const_get(c)} v = case when pkg.const_defined?(:Version) pkg.const_get(n = :Version) when pkg.const_defined?(:VERSION) pkg.const_get(n = :VERSION) else n = nil "unknown" end show.call(pkg, n, v) rescue NameError end end end result end
# File optparse.rb, line 1078 def self.terminate(arg = nil) throw :terminate, arg end
Initializes a new instance and evaluates the optional block in context of
the instance. Arguments args
are passed to new, see there for description of
parameters.
This method is deprecated, its behavior corresponds to the older new method.
# File optparse.rb, line 1025 def self.with(*args, &block) opts = new(*args) opts.instance_eval(&block) opts end
# File optparse.rb, line 1192 def abort(mesg = $!) super("#{program_name}: #{mesg}") end
Directs to accept specified class t
. The argument string is
passed to the block in which it should be converted to the desired class.
t
Argument class specifier, any object including Class.
pat
Pattern for argument, defaults to t
if it responds to match.
accept(t, pat, &block)
# File optparse.rb, line 1094 def accept(*args, &blk) top.accept(*args, &blk) end
Subject of on_tail.
# File optparse.rb, line 1206 def base @stack[1] end
# File optparse.rb, line 1743 def candidate(word) list = [] case word when /\A--/ word, arg = word.split(/=/, 2) argpat = Completion.regexp(arg, false) if arg and !arg.empty? long = true when /\A-(!-)/ short = true when /\A-/ long = short = true end pat = Completion.regexp(word, true) visit(:each_option) do |opt| next unless Switch === opt opts = (long ? opt.long : []) + (short ? opt.short : []) opts = Completion.candidate(word, true, pat, &opts.method(:each)).map(&:first) if pat if /\A=/ =~ opt.arg opts.map! {|sw| sw + "="} if arg and CompletingHash === opt.pattern if opts = opt.pattern.candidate(arg, false, argpat) opts.map!(&:last) end end end list.concat(opts) end list end
# File optparse.rb, line 1464 def define(*opts, &block) top.append(*(sw = make_switch(opts, block))) sw[0] end
# File optparse/kwargs.rb, line 4 def define_by_keywords(options, meth, **opts) meth.parameters.each do |type, name| case type when :key, :keyreq op, cl = *(type == :key ? %w"[ ]" : ["", ""]) define("--#{name}=#{op}#{name.upcase}#{cl}", *opts[name]) do |o| options[name] = o end end end options end
# File optparse.rb, line 1479 def define_head(*opts, &block) top.prepend(*(sw = make_switch(opts, block))) sw[0] end
# File optparse.rb, line 1493 def define_tail(*opts, &block) base.append(*(sw = make_switch(opts, block))) sw[0] end
Parses environment variable env
or its uppercase with
splitting like a shell.
env
defaults to the basename of the program.
# File optparse.rb, line 1800 def environment(env = File.basename($0, '.*')) env = ENV[env] || ENV[env.upcase] or return require 'shellwords' parse(*Shellwords.shellwords(env)) end
Wrapper method for getopts.rb.
params = ARGV.getopts("ab:", "foo", "bar:", "zot:Z;zot option") # params[:a] = true # -a # params[:b] = "1" # -b1 # params[:foo] = "1" # --foo # params[:bar] = "x" # --bar x # params[:zot] = "z" # --zot Z
# File optparse.rb, line 1661 def getopts(*args) argv = Array === args.first ? args.shift : default_argv single_options, *long_options = *args result = {} single_options.scan(/(.)(:)?/) do |opt, val| if val result[opt] = nil define("-#{opt} VAL") else result[opt] = false define("-#{opt}") end end if single_options long_options.each do |arg| arg, desc = arg.split(';', 2) opt, val = arg.split(':', 2) if val result[opt] = val.empty? ? nil : val define("--#{opt}=#{result[opt] || "VAL"}", *[desc].compact) else result[opt] = false define("--#{opt}", *[desc].compact) end end parse_in_order(argv, result.method(:[]=)) result end
Returns option summary string.
# File optparse.rb, line 1247 def help; summarize("#{banner}".sub(/\n?\z/, "\n")) end
# File optparse.rb, line 1042 def inc(*args) self.class.inc(*args) end
Loads options from file names as filename
. Does nothing when
the file is not present. Returns whether successfully loaded.
filename
defaults to basename of the program without suffix in
a directory ~/.options.
# File optparse.rb, line 1780 def load(filename = nil) begin filename ||= File.expand_path(File.basename($0, '.*'), '~/.options') rescue return false end begin parse(*IO.readlines(filename).each {|s| s.chomp!}) true rescue Errno::ENOENT, Errno::ENOTDIR false end end
Creates an OptionParser::Switch from the parameters. The parsed argument value is passed to the given block, where it can be processed.
See at the beginning of OptionParser for some full examples.
opts
can include the following elements:
One of the following:
:NONE, :REQUIRED, :OPTIONAL
Acceptable option argument format, must be pre-defined with #accept or #accept, or Regexp. This can appear once or assigned as String if not present, otherwise causes an ArgumentError. Examples:
Float, Time, Array
Hash or Array.
[:text, :binary, :auto] %w[iso-2022-jp shift_jis euc-jp utf8 binary] { "jis" => "iso-2022-jp", "sjis" => "shift_jis" }
Specifies a long style switch which takes a mandatory, optional or no argument. It's a string of the following form:
"--switch=MANDATORY" or "--switch MANDATORY" "--switch[=OPTIONAL]" "--switch"
Specifies short style switch which takes a mandatory, optional or no argument. It's a string of the following form:
"-xMANDATORY" "-x[OPTIONAL]" "-x"
There is also a special form which matches character range (not full set of regular expression):
"-[a-z]MANDATORY" "-[a-z][OPTIONAL]" "-[a-z]"
Instead of specifying mandatory or optional arguments directly in the switch parameter, this separate parameter can be used.
"=MANDATORY" "=[OPTIONAL]"
Description string for the option.
"Run verbosely"
Handler for the parsed argument value. Either give a block or pass a Proc or Method as an argument.
# File optparse.rb, line 1331 def make_switch(opts, block = nil) short, long, nolong, style, pattern, conv, not_pattern, not_conv, not_style = [], [], [] ldesc, sdesc, desc, arg = [], [], [] default_style = Switch::NoArgument default_pattern = nil klass = nil q, a = nil has_arg = false opts.each do |o| # argument class next if search(:atype, o) do |pat, c| klass = notwice(o, klass, 'type') if not_style and not_style != Switch::NoArgument not_pattern, not_conv = pat, c else default_pattern, conv = pat, c end end # directly specified pattern(any object possible to match) if (!(String === o || Symbol === o)) and o.respond_to?(:match) pattern = notwice(o, pattern, 'pattern') if pattern.respond_to?(:convert) conv = pattern.method(:convert).to_proc else conv = SPLAT_PROC end next end # anything others case o when Proc, Method block = notwice(o, block, 'block') when Array, Hash case pattern when CompletingHash when nil pattern = CompletingHash.new conv = pattern.method(:convert).to_proc if pattern.respond_to?(:convert) else raise ArgumentError, "argument pattern given twice" end o.each {|pat, *v| pattern[pat] = v.fetch(0) {pat}} when Module raise ArgumentError, "unsupported argument type: #{o}", ParseError.filter_backtrace(caller(4)) when *ArgumentStyle.keys style = notwice(ArgumentStyle[o], style, 'style') when /^--no-([^\[\]=\s]*)(.+)?/ q, a = $1, $2 o = notwice(a ? Object : TrueClass, klass, 'type') not_pattern, not_conv = search(:atype, o) unless not_style not_style = (not_style || default_style).guess(arg = a) if a default_style = Switch::NoArgument default_pattern, conv = search(:atype, FalseClass) unless default_pattern ldesc << "--no-#{q}" (q = q.downcase).tr!('_', '-') long << "no-#{q}" nolong << q when /^--\[no-\]([^\[\]=\s]*)(.+)?/ q, a = $1, $2 o = notwice(a ? Object : TrueClass, klass, 'type') if a default_style = default_style.guess(arg = a) default_pattern, conv = search(:atype, o) unless default_pattern end ldesc << "--[no-]#{q}" (o = q.downcase).tr!('_', '-') long << o not_pattern, not_conv = search(:atype, FalseClass) unless not_style not_style = Switch::NoArgument nolong << "no-#{o}" when /^--([^\[\]=\s]*)(.+)?/ q, a = $1, $2 if a o = notwice(NilClass, klass, 'type') default_style = default_style.guess(arg = a) default_pattern, conv = search(:atype, o) unless default_pattern end ldesc << "--#{q}" (o = q.downcase).tr!('_', '-') long << o when /^-(\[\^?\]?(?:[^\\\]]|\\.)*\])(.+)?/ q, a = $1, $2 o = notwice(Object, klass, 'type') if a default_style = default_style.guess(arg = a) default_pattern, conv = search(:atype, o) unless default_pattern else has_arg = true end sdesc << "-#{q}" short << Regexp.new(q) when /^-(.)(.+)?/ q, a = $1, $2 if a o = notwice(NilClass, klass, 'type') default_style = default_style.guess(arg = a) default_pattern, conv = search(:atype, o) unless default_pattern end sdesc << "-#{q}" short << q when /^=/ style = notwice(default_style.guess(arg = o), style, 'style') default_pattern, conv = search(:atype, Object) unless default_pattern else desc.push(o) end end default_pattern, conv = search(:atype, default_style.pattern) unless default_pattern if !(short.empty? and long.empty?) if has_arg and default_style == Switch::NoArgument default_style = Switch::RequiredArgument end s = (style || default_style).new(pattern || default_pattern, conv, sdesc, ldesc, arg, desc, block) elsif !block if style or pattern raise ArgumentError, "no switch given", ParseError.filter_backtrace(caller) end s = desc else short << pattern s = (style || default_style).new(pattern, conv, nil, nil, arg, desc, block) end return s, short, long, (not_style.new(not_pattern, not_conv, sdesc, ldesc, nil, desc, block) if not_style), nolong end
Pushes a new List.
# File optparse.rb, line 1213 def new @stack.push(List.new) if block_given? yield self else self end end
Add option switch and handler. See make_switch for an explanation of parameters.
# File optparse.rb, line 1473 def on(*opts, &block) define(*opts, &block) self end
Add option switch like with on, but at head of summary.
# File optparse.rb, line 1487 def on_head(*opts, &block) define_head(*opts, &block) self end
Add option switch like with on, but at tail of summary.
# File optparse.rb, line 1501 def on_tail(*opts, &block) define_tail(*opts, &block) self end
Parses command line arguments argv
in order. When a block is
given, each non-option argument is yielded.
Returns the rest of argv
left unparsed.
# File optparse.rb, line 1520 def order(*argv, into: nil, &nonopt) argv = argv[0].dup if argv.size == 1 and Array === argv[0] order!(argv, into: into, &nonopt) end
Same as order, but removes
switches destructively. Non-option arguments remain in argv
.
# File optparse.rb, line 1529 def order!(argv = default_argv, into: nil, &nonopt) setter = ->(name, val) {into[name.to_sym] = val} if into parse_in_order(argv, setter, &nonopt) end
Parses command line arguments argv
in order when environment
variable POSIXLY_CORRECT is set, and in permutation mode otherwise.
# File optparse.rb, line 1634 def parse(*argv, into: nil) argv = argv[0].dup if argv.size == 1 and Array === argv[0] parse!(argv, into: into) end
Same as parse, but removes
switches destructively. Non-option arguments remain in argv
.
# File optparse.rb, line 1643 def parse!(argv = default_argv, into: nil) if ENV.include?('POSIXLY_CORRECT') order!(argv, into: into) else permute!(argv, into: into) end end
Parses command line arguments argv
in permutation mode and
returns list of non-option arguments.
# File optparse.rb, line 1614 def permute(*argv, into: nil) argv = argv[0].dup if argv.size == 1 and Array === argv[0] permute!(argv, into: into) end
Same as permute, but
removes switches destructively. Non-option arguments remain in
argv
.
# File optparse.rb, line 1623 def permute!(argv = default_argv, into: nil) nonopts = [] order!(argv, into: into, &nonopts.method(:<<)) argv[0, 0] = nonopts argv end
Program name to be emitted in error message and default banner, defaults to $0.
# File optparse.rb, line 1148 def program_name @program_name || File.basename($0, '.*') end
Directs to reject specified class argument.
t
Argument class specifier, any object including Class.
reject(t)
# File optparse.rb, line 1107 def reject(*args, &blk) top.reject(*args, &blk) end
Release code
# File optparse.rb, line 1173 def release @release || (defined?(::Release) && ::Release) || (defined?(::RELEASE) && ::RELEASE) end
Removes the last List.
# File optparse.rb, line 1225 def remove @stack.pop end
Add separator in summary.
# File optparse.rb, line 1510 def separator(string) top.append(string, nil, nil) end
Puts option summary into to
and returns to
.
Yields each line if a block is given.
to
Output destination, which must have method <<. Defaults to [].
width
Width of left side, defaults to @summary_width.
max
Maximum length allowed for left side, defaults to width
- 1.
indent
Indentation, defaults to @summary_indent.
# File optparse.rb, line 1238 def summarize(to = [], width = @summary_width, max = width - 1, indent = @summary_indent, &blk) blk ||= proc {|l| to << (l.index($/, -1) ? l : l + $/)} visit(:summarize, {}, {}, width, max, indent, &blk) to end
Terminates option parsing. Optional parameter arg
is a string
pushed back to be the first non-option argument.
# File optparse.rb, line 1075 def terminate(arg = nil) self.class.terminate(arg) end
Returns option summary list.
# File optparse.rb, line 1253 def to_a; summarize("#{banner}".split(/^/)) end
Returns version string from #program_name, version and release.
# File optparse.rb, line 1180 def ver if v = version str = "#{program_name} #{[v].join('.')}" str << " (#{v})" if v = release str end end