README.md
1 argparse 2 ======== 3 4 [](http://travis-ci.org/nodeca/argparse) 5 [](https://www.npmjs.org/package/argparse) 6 7 CLI arguments parser for node.js. Javascript port of python's 8 [argparse](http://docs.python.org/dev/library/argparse.html) module 9 (original version 3.2). That's a full port, except some very rare options, 10 recorded in issue tracker. 11 12 **NB. Difference with original.** 13 14 - Method names changed to camelCase. See [generated docs](http://nodeca.github.com/argparse/). 15 - Use `defaultValue` instead of `default`. 16 - Use `argparse.Const.REMAINDER` instead of `argparse.REMAINDER`, and 17 similarly for constant values `OPTIONAL`, `ZERO_OR_MORE`, and `ONE_OR_MORE` 18 (aliases for `nargs` values `'?'`, `'*'`, `'+'`, respectively), and 19 `SUPPRESS`. 20 21 22 Example 23 ======= 24 25 test.js file: 26 27 ```javascript 28 #!/usr/bin/env node 29 'use strict'; 30 31 var ArgumentParser = require('../lib/argparse').ArgumentParser; 32 var parser = new ArgumentParser({ 33 version: '0.0.1', 34 addHelp:true, 35 description: 'Argparse example' 36 }); 37 parser.addArgument( 38 [ '-f', '--foo' ], 39 { 40 help: 'foo bar' 41 } 42 ); 43 parser.addArgument( 44 [ '-b', '--bar' ], 45 { 46 help: 'bar foo' 47 } 48 ); 49 parser.addArgument( 50 '--baz', 51 { 52 help: 'baz bar' 53 } 54 ); 55 var args = parser.parseArgs(); 56 console.dir(args); 57 ``` 58 59 Display help: 60 61 ``` 62 $ ./test.js -h 63 usage: example.js [-h] [-v] [-f FOO] [-b BAR] [--baz BAZ] 64 65 Argparse example 66 67 Optional arguments: 68 -h, --help Show this help message and exit. 69 -v, --version Show program's version number and exit. 70 -f FOO, --foo FOO foo bar 71 -b BAR, --bar BAR bar foo 72 --baz BAZ baz bar 73 ``` 74 75 Parse arguments: 76 77 ``` 78 $ ./test.js -f=3 --bar=4 --baz 5 79 { foo: '3', bar: '4', baz: '5' } 80 ``` 81 82 More [examples](https://github.com/nodeca/argparse/tree/master/examples). 83 84 85 ArgumentParser objects 86 ====================== 87 88 ``` 89 new ArgumentParser({parameters hash}); 90 ``` 91 92 Creates a new ArgumentParser object. 93 94 **Supported params:** 95 96 - ```description``` - Text to display before the argument help. 97 - ```epilog``` - Text to display after the argument help. 98 - ```addHelp``` - Add a -h/–help option to the parser. (default: true) 99 - ```argumentDefault``` - Set the global default value for arguments. (default: null) 100 - ```parents``` - A list of ArgumentParser objects whose arguments should also be included. 101 - ```prefixChars``` - The set of characters that prefix optional arguments. (default: ‘-‘) 102 - ```formatterClass``` - A class for customizing the help output. 103 - ```prog``` - The name of the program (default: `path.basename(process.argv[1])`) 104 - ```usage``` - The string describing the program usage (default: generated) 105 - ```conflictHandler``` - Usually unnecessary, defines strategy for resolving conflicting optionals. 106 107 **Not supported yet** 108 109 - ```fromfilePrefixChars``` - The set of characters that prefix files from which additional arguments should be read. 110 111 112 Details in [original ArgumentParser guide](http://docs.python.org/dev/library/argparse.html#argumentparser-objects) 113 114 115 addArgument() method 116 ==================== 117 118 ``` 119 ArgumentParser.addArgument(name or flag or [name] or [flags...], {options}) 120 ``` 121 122 Defines how a single command-line argument should be parsed. 123 124 - ```name or flag or [name] or [flags...]``` - Either a positional name 125 (e.g., `'foo'`), a single option (e.g., `'-f'` or `'--foo'`), an array 126 of a single positional name (e.g., `['foo']`), or an array of options 127 (e.g., `['-f', '--foo']`). 128 129 Options: 130 131 - ```action``` - The basic type of action to be taken when this argument is encountered at the command line. 132 - ```nargs```- The number of command-line arguments that should be consumed. 133 - ```constant``` - A constant value required by some action and nargs selections. 134 - ```defaultValue``` - The value produced if the argument is absent from the command line. 135 - ```type``` - The type to which the command-line argument should be converted. 136 - ```choices``` - A container of the allowable values for the argument. 137 - ```required``` - Whether or not the command-line option may be omitted (optionals only). 138 - ```help``` - A brief description of what the argument does. 139 - ```metavar``` - A name for the argument in usage messages. 140 - ```dest``` - The name of the attribute to be added to the object returned by parseArgs(). 141 142 Details in [original add_argument guide](http://docs.python.org/dev/library/argparse.html#the-add-argument-method) 143 144 145 Action (some details) 146 ================ 147 148 ArgumentParser objects associate command-line arguments with actions. 149 These actions can do just about anything with the command-line arguments associated 150 with them, though most actions simply add an attribute to the object returned by 151 parseArgs(). The action keyword argument specifies how the command-line arguments 152 should be handled. The supported actions are: 153 154 - ```store``` - Just stores the argument’s value. This is the default action. 155 - ```storeConst``` - Stores value, specified by the const keyword argument. 156 (Note that the const keyword argument defaults to the rather unhelpful None.) 157 The 'storeConst' action is most commonly used with optional arguments, that 158 specify some sort of flag. 159 - ```storeTrue``` and ```storeFalse``` - Stores values True and False 160 respectively. These are special cases of 'storeConst'. 161 - ```append``` - Stores a list, and appends each argument value to the list. 162 This is useful to allow an option to be specified multiple times. 163 - ```appendConst``` - Stores a list, and appends value, specified by the 164 const keyword argument to the list. (Note, that the const keyword argument defaults 165 is None.) The 'appendConst' action is typically used when multiple arguments need 166 to store constants to the same list. 167 - ```count``` - Counts the number of times a keyword argument occurs. For example, 168 used for increasing verbosity levels. 169 - ```help``` - Prints a complete help message for all the options in the current 170 parser and then exits. By default a help action is automatically added to the parser. 171 See ArgumentParser for details of how the output is created. 172 - ```version``` - Prints version information and exit. Expects a `version=` 173 keyword argument in the addArgument() call. 174 175 Details in [original action guide](http://docs.python.org/dev/library/argparse.html#action) 176 177 178 Sub-commands 179 ============ 180 181 ArgumentParser.addSubparsers() 182 183 Many programs split their functionality into a number of sub-commands, for 184 example, the svn program can invoke sub-commands like `svn checkout`, `svn update`, 185 and `svn commit`. Splitting up functionality this way can be a particularly good 186 idea when a program performs several different functions which require different 187 kinds of command-line arguments. `ArgumentParser` supports creation of such 188 sub-commands with `addSubparsers()` method. The `addSubparsers()` method is 189 normally called with no arguments and returns an special action object. 190 This object has a single method `addParser()`, which takes a command name and 191 any `ArgumentParser` constructor arguments, and returns an `ArgumentParser` object 192 that can be modified as usual. 193 194 Example: 195 196 sub_commands.js 197 ```javascript 198 #!/usr/bin/env node 199 'use strict'; 200 201 var ArgumentParser = require('../lib/argparse').ArgumentParser; 202 var parser = new ArgumentParser({ 203 version: '0.0.1', 204 addHelp:true, 205 description: 'Argparse examples: sub-commands', 206 }); 207 208 var subparsers = parser.addSubparsers({ 209 title:'subcommands', 210 dest:"subcommand_name" 211 }); 212 213 var bar = subparsers.addParser('c1', {addHelp:true}); 214 bar.addArgument( 215 [ '-f', '--foo' ], 216 { 217 action: 'store', 218 help: 'foo3 bar3' 219 } 220 ); 221 var bar = subparsers.addParser( 222 'c2', 223 {aliases:['co'], addHelp:true} 224 ); 225 bar.addArgument( 226 [ '-b', '--bar' ], 227 { 228 action: 'store', 229 type: 'int', 230 help: 'foo3 bar3' 231 } 232 ); 233 234 var args = parser.parseArgs(); 235 console.dir(args); 236 237 ``` 238 239 Details in [original sub-commands guide](http://docs.python.org/dev/library/argparse.html#sub-commands) 240 241 242 Contributors 243 ============ 244 245 - [Eugene Shkuropat](https://github.com/shkuropat) 246 - [Paul Jacobson](https://github.com/hpaulj) 247 248 [others](https://github.com/nodeca/argparse/graphs/contributors) 249 250 License 251 ======= 252 253 Copyright (c) 2012 [Vitaly Puzrin](https://github.com/puzrin). 254 Released under the MIT license. See 255 [LICENSE](https://github.com/nodeca/argparse/blob/master/LICENSE) for details. 256 257