-- script.lua
local argparse = require "argparse"

local parser = argparse:new()
parser:argument "input"
parser:option "-o" "--output"

local args = parser:parse()
for k, v in pairs(args) do
   print(k, v)
end

Does it work?

$ lua script.lua -o out.txt in.txt

input	in.txt
output	out.txt

There are several ways to pass options.

$ lua script.lua --output out.txt in.txt
$ lua script.lua in.txt --output=out.txt
$ lua script.lua in.txt -oout.txt

Does it provide help?

$ lua script.lua --help

Usage: test.lua [-o <output>] [-h] <input>

Arguments: 
   input

Options: 
   -o <output>, --output <output>
   -h, --help            Show this help message and exit.

What if we do something wrong?

$ lua script.lua foo bar

Usage: test.lua [-o <output>] [-h] <input>

Error: too many arguments

What if we make a typo?

$ lua script.lua in.txt --outptu out.txt

Usage: test.lua [-o <output>] [-h] <input>

Error: unknown option '--outptu'
Did you mean '--output'?

Installation

Using luarocks

Installing argparse using luarocks is will be easy.

luarocks install argparse

Problems with old luarocks versions

You may get an error like Parse error processing dependency '30log >= 0.8' if you use luarocks 2.1 or older. In this case, either upgrade to at least luarocks 2.1.1 or install 30log manually, then download the rockspec for argparse, remove the line "30log >= 0.8" and run

luarocks install /path/to/argparse/rockspec

Without luarocks

Download /src/argparse.lua file and put it into the directory for libraries or your working directory. Install 30log using luarocks or manually download 30log.lua file from 30log repo.

Documentation

Documentation is availible in the doc directory and online. If argparse was installed using luarocks 2.1.2 or later, it can be viewed using luarocks doc argparse command.

Testing

argparse comes with a testing suite located in spec directory. busted is required for testing, it can be installed using luarocks. Run the tests using busted spec command from the argparse folder.