cliargs is a command-line argument parser for Lua. It supports several types of arguments:
- required arguments
- optional arguments with different notations:
- optional arguments with multiple-values that get appended to a list
- optional "flag" arguments (on/off options) with notations:
- a single optional "splat" argument which can be repeated (must be the last argument)
Optional arguments can have default values (strings), flags always default to 'true'.
See the examples under the
See http://lua-cliargs.netlify.com/ for the API docs.
A help listing will be automatically generated and accessed using the
--help argument. When such an option is encountered,
cli:parse() will abort and return
nil, string with the help message; you are free to print it to the screen using
print() if you want.
You can also force its display in the code using
This is the result for our example (see
Usage: cli_example.lua [OPTIONS] INPUT [OUTPUT-1 [OUTPUT-2 [...]]] ARGUMENTS: INPUT path to the input file (required) OUTPUT multiple output paths (optional, default: /dev/stdout) OPTIONS: -c, --compress=FILTER the filter to use for compressing output: gzip, lzma, bzip2, or none (default: gzip) -o FILE path to output file (default: /dev/stdout) -d script will run in DEBUG mode -v, --version prints the program's version and exits --verbose the script output will be very verbose
Runtime argument validation
From a parsing point of view, there are 3 cases that need to be handled which are outlined below. If I missed something, please open a ticket!
Missing a required argument
$ lua examples/00_general.lua cli_example.lua: error: bad number of arguments; 1-4 argument(s) must be specified, not 0; re-run with --help for usage.
Missing value for an optional argument
$ lua examples/00_general.lua --compress inputfile cli_example.lua: error: option --compress requires a value to be set; re-run with --help for usage.
$ lua examples/00_general.lua -f inputfile cli_example.lua: error: unknown/bad flag; -f; re-run with --help for usage.
Some sanity guards
In the following cases,
cliargs will report an error to you and terminate the running script:
- flag options can not accept a value. For example:
cli:add_flag('-v VERSION')will return an error
- duplicate keys are not allowed: defining two options with the key
--inputwill be rejected
luarocks install busted cd /path/to/lua_cliargs/ busted spec
If you come across a bug and you'd like to patch it, please fork the repository, commit your patch, and request a pull.
Many thanks to everyone who reported bugs, provided fixes, and added entirely new features:
If I missed you, don't hesitate to update this file or just email me.
Changes from 2.5.x 3.0
This major version release contains BREAKING API CHANGES. See the UPGRADE guide for help in updating your code to make use of it.
More flexible parsing
- options can occur anywhere now even after arguments (unless the
--indicator is specified, then no options are parsed afterwards.) Previously, options were accepted only before arguments.
- options using the short-key notation can be specified using
=as a value delimiter as well as a space (e.g.
- the library is now more flexible with option definitions (notations like
-k=VALUEare all treated equally)
-hwill now cause the help listing to be displayed no matter where they are. Previously, this only happened if they were supplied as the first option.
Basic command support
You may now define commands with custom handlers. A command may be invoked by supplying its name as the first argument (options can still come before or afterwards). lua_cliargs will forward the rest of the options to that command to handle, which can be in a separate file.
examples/04_commands--git.lua for an example.
It is now possible to pass a table containing default values (and override any existing defaults).
The function for doing this is called
This makes it possible to load run-time defaults from a configuration file, for example.
Reading configuration files
cliargs now exposes some convenience helpers for loading configuration from files (and a separate hook,
cli:load_defaults() to inject this config if you want) found in
cli:read_defaults(). This method takes a file-path and an optional file format and it will parse it for you, provided you have the necessary libraries installed.
See the API docs for using this hook.
- internal code changes and more comprehensive test-coverage
Changes from 2.5.1 to 2.5.2
- No longer tracking the (legacy) tarballs in git or the luarocks package. Instead, we use the GitHub release tarballs for each version.
Changes in 2.4.0 from 2.3-4
- All arguments now accept a callback that will be invoked when parsing of those arguments was successful
- (POSSIBLY BREAKING) Default value for flags is now
false. This will only affect existing behavior if you were explicitly testing unset flags to equal
if flag == false then) as opposed to
if flag then(or
if not flag then).
- Minor bugfixes
Changes in 2.3.0
- the parser will now understand
--to denote the end of optional arguments and will map whatever comes after it to required/splat args
-short VALUEis now properly supported, so is
- short-key options can now officially be composed of more than 1 character
- the parser now accepts callbacks that will be invoked as soon as options are parsed so that you can bail out of parsing preemptively (like for
- options can now accept multiple values via multiple invocations if a table was provided as a default value (passed-in values will be appended to that list)
Changes in 2.2-0 from 2.1-2
=that separates keys from values in the
--expanded-keynotation is no longer mandatory; using either a space or a
=will map the value to the key (e.g.,
--compress lzmais equal to
Changes in 2.0.0 from 1.x.x
- added the 'splat' argument, an optional repetitive argument for which a maximum number of occurrences can be set
- removed the reference, arguments are now solely returned by their key/expanded-key (BREAKING!)
- removed object overhead and the
new()method as the library will only be used once on program start-up (BREAKING!)
- after parsing completed successfully, the library will effectively delete itself to free resources (BREAKING!)
- option/flag is now allowed with only an expanded-key defined
- Debug aid implemented; adding a first option
--__DUMP__, will dump the results of parsing the command line. Especially for testing how to use the commandline with arguments containing spaces either quoted or not.
print_help()now have a 'noprint' parameter that will not print the message, but return it as an error string (
nil + errmsg)
The code is released under the MIT terms. Feel free to use it in both open and closed software as you please.
Copyright (c) 2011-2015 Ahmad Amireh
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.