Argc

An elegant command-line options, arguments and sub-commands parser for bash.

Install

With cargo

cargo install argc

Binaries on macOS, Linux, Windows

Download from Github Releases, unzip and add argc to your $PATH.

GitHub Actions

extractions/setup-crate can be used to install just in a GitHub Actions workflow.

- uses: extractions/setup-crate@v1
  with:
    owner: sigoden
    name: argc

Usage

To write a command-line program with argc, we only need to do two things:

1. Describe options, flags, positional parameters and subcommands in comments.
2. Insert eval "$(argc --argc-eval "$0" "$@")" into script to let argc to parse command line arguments.

Write example.sh

# @flag   --foo   Flag value
# @option --bar   Option value
# @arg baz*       Positional values

eval "$(argc --argc-eval "$0" "$@")"
echo foo: $argc_foo
echo bar: $argc_bar
echo baz: ${argc_baz[@]}

Run ./example.sh --foo --bar=xyz a b c, you can see argc successfully parses arguments and generate variables with argc_ prefix.

foo: 1
bar: xyz
baz: a b c

Run ./example.sh -h, argc wll print help information for you.

USAGE: example.sh [OPTIONS] [BAZ]...

ARGS:
  [BAZ]...  Positional values

OPTIONS:
      --foo        Flag value
      --bar <BAR>  Option value
  -h, --help       Print help

Comment Tags

argc parses cli definition from comment tags.

@cmd

Define a subcommand

# @cmd Upload a file
upload() {
  echo Run upload
}

# @cmd Download a file
download() {
  echo Run download
}

USAGE: test.sh <COMMAND>

COMMANDS:
  upload    Upload a file
  download  Download a file

@arg

Define a positional argument.

# @arg va
# @arg vb!                 required
# @arg vc*                 multi-values
# @arg vd+                 multi-values + required
# @arg vna <PATH>          value notation
# @arg vda=a               default
# @arg vca[a|b]            choices
# @arg vcb[=a|b]           choices + default
# @arg vx~                 capture all remaining args

@option

Define a option.

# @option    --oa                   
# @option -b --ob                   short
# @option -c                        short only
# @option    --oc!                  required
# @option    --od*                  multi-occurs
# @option    --oe+                  multi-occurs + required
# @option    --ona <PATH>           value notation
# @option    --onb <FILE> <FILE>    two-args value notations
# @option    --oda=a                default
# @option    --oca[a|b]             choices
# @option    --ocb[=a|b]            choices + default
# @option    --oxa~                 capture all remaining args

@flag

Define a flag. A flag is an option of boolean type, and is always false by default (e.g. --verbose, --quiet, --all, --long, etc).

# @flag     --fa 
# @flag  -b --fb         short
# @flag  -c              short only
# @flag     --fd*        multi-occurs

@alias

Add aliases for subcommand.

# @cmd Run tests
# @alias t,tst
test() {
  echo Run test
}

USAGE: test.sh <COMMAND>

COMMANDS:
  test  Run tests [aliases: t, tst]

@describe / @version / @author

# @describe A demo cli
# @version 2.17.1 
# @author nobody <nobody@example.com>

# @cmd Run test
test() {
  echo Run test
}

test.sh 2.17.1
nobody <nobody@example.com>
A demo cli

USAGE: test.sh <COMMAND>

COMMANDS:
  test  Run test

@meta

Add metadata

# @meta combine-shorts
# @meta inherit-flag-options

Value Notation

Value notation is used to describe value type of options and positional parameters.

# @option --target <FILE>
# @arg target <FILE>

Here are some value notation that will affect the shell completion.

• FILE/PATH: complete files
• DIR: complete directories

Shell Completion

Argc provides shell completion for argc command and all the bash scripts powered by argc.

# bash (~/.bashrc)
source <(argc --argc-completions bash mycmd1 mycmd2)

# elvish (~/.config/elvish/rc.elv)
eval (argc --argc-completions elvish mycmd1 mycmd2 | slurp)

# fish (~/.config/fish/config.fish)
argc --argc-completions fish mycmd1 mycmd2 | source

# nushell (~/.config/nushell/config.nu)
argc --argc-completions nushell mycmd1 mycmd2 # update config.nu manually according to output

# powershell ($PROFILE)
Set-PSReadlineKeyHandler -Key Tab -Function MenuComplete
argc --argc-completions powershell mycmd1 mycmd2 | Out-String | Invoke-Expression

# xonsh (~/.config/xonsh/rc.xsh)
exec($(argc --argc-completions xonsh mycmd1 mycmd2))

# zsh (~/.zshrc)
source <(argc --argc-completions zsh mycmd1 mycmd2)

# tcsh (~/.tcshrc)
eval `argc --argc-completions tcsh mycmd1 mycmd2`

Replace mycmd1 mycmd2 with your argc scripts.

Argc can be used as multiple shell completion engine. see argc-completions

Argcscript

Argc will automatically find and run Argcfile.sh unless --argc-* options are used to change this behavior.

Argcfile is to argc what Makefile is to make.

what is the benefit?

• Can enjoy a handy shell completion.
• Can be invoked in arbitrarily subdirectory, no need to locate script file each time.
• As a centralized entrypoint/document for executing the project's bash scripts.
• Serves as a script for a task runner.

You can use argc --argc-create to quickly create a boilerplate argcscript.

Parallel

argc provides features for running commands/functions in parallel.

argc --argc-parallel "$0" cmd1 arg1 arg2 ::: cmd2

The above command will run cmd1 arg1 arg2 and cmd2 in parallel. Functions running in parallel mode can still access the argc_* variable.

Windows Only

Argc requires bash to run scripts. git's built-in bash is good enough for argc.

If you want to run a .sh script file directly like a .cmd or .exe file, execute the following code in PowerShell.

# Add .sh to PATHEXT
[Environment]::SetEnvironmentVariable("PATHEXT", [Environment]::GetEnvironmentVariable("PATHEXT", "Machine") + ";.SH", "Machine")

# Associate the .sh file extension with Git Bash
New-Item -LiteralPath Registry::HKEY_CLASSES_ROOT\.sh -Force
New-ItemProperty -LiteralPath Registry::HKEY_CLASSES_ROOT\.sh -Name "(Default)" -Value "sh_auto_file" -PropertyType String -Force
New-ItemProperty -LiteralPath 'HKLM:\SOFTWARE\Classes\sh_auto_file\shell\open\command' `
  -Name '(default)' -Value '"C:\Program Files\Git\bin\bash.exe" "%1" %*' -PropertyType String -Force

License

argc is made available under the terms of either the MIT License or the Apache License 2.0, at your option.

See the LICENSE-APACHE and LICENSE-MIT files for license details.