# Argc
[](https://github.com/sigoden/argc/actions/workflows/ci.yaml)
[](https://crates.io/crates/argc)
Easily create a feature-rich command-line application in Bash.
## Install
### With cargo
```
cargo install argc
```
### Binaries on macOS, Linux, Windows
Download from [Github Releases](https://github.com/sigoden/argc/releases), unzip and add argc to your $PATH.
### GitHub Actions
[extractions/setup-crate](https://github.com/marketplace/actions/setup-crate) can be used to install just in a GitHub Actions workflow.
```yaml
- uses: extractions/setup-crate@v1
with:
owner: sigoden
name: argc
```
## Usage
To write a command-line program with argc, we only need to do two things:
1. Describe options, flags, positional parameters and subcommands in comments.
2. Insert `eval "$(argc "$0" "$@")"` into script to let argc to parse command line arguments.
Write `example.sh`
```sh
# @flag --foo A flag
# @option --bar A option
# @option --baz* A option with multiple values
eval "$(argc "$0" "$@")"
echo foo: $argc_foo
echo bar: $argc_bar
echo baz: ${argc_baz[@]}
```
Run `./example.sh --foo --bar=value --baz a b c`, you can see argc successfully parses arguments and generate variables with `argc_` prefix.
```
foo: 1
bar: value
baz: a b c
```
Run `example.sh -h`, argc wll print help information for you.
```
USAGE: example.sh [OPTIONS]
OPTIONS:
--foo A flag
--bar <BAR> A option
--baz [<BAZ>...] A option with multiple values
-h, --help Print help information
```
## Comment Tags
`argc` parses cli definition from comment tags.
### @cmd
```
@cmd [string]
```
Define a subcommand
```sh
# @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
```
@arg <name>[modifier] [value notation] [help string]
```
Define a positional argument.
```sh
# @arg arg1 A positional argument
# @arg arg2! A required positional argument
# @arg arg3 <PATH> A positional argument with value notation
# @arg arg4* A positional argument support multiple values
# @arg arg5+ A required positional argument support multiple values
# @arg arg6=a A positional argument with default value
# @arg arg7=`_fn` A positional argument with default value from fn
# @arg arg8[a|b] A positional argument with choices
# @arg arg9[`_fn`] A positional argument with choices from fn
# @arg arg10[=a|b] A positional argument with choices and default value
# @arg arg11![a|b] A required positional argument with choices
# @arg arg12![`_fn`] A required positional argument with choices from fn
```
### @option
```
@option [short] <long>[modifier] [value notation] [help string]
```
Define a option.
```sh
# @option --opt1 A option
# @option -a --opt2 A option with short alias
# @option --opt3 <PATH> A option with value notation
# @option --opt4! A required option
# @option --opt5* A option with multiple values
# @option --opt6+ A required option with multiple values
# @option --opt7=a A option with default value
# @option --opt8=`_fn` A option with default value from fn
# @option --opt9[a|b] A option with choices
# @option --opt10[`_fn`] A option with choices from fn
# @option --opt11[=a|b] A option with choices and default value
# @option --opt12![a|b] A required option with choices
# @option --opt13![`_fn`] A required option with choices from fn
# @option -b --opt14 <PATH> A option with short alias and value notation
```
### @flag
```
@flag [short] <long> [help string]
```
Define a flag. A flag is an option of boolean type, and is always false by default (e.g. --verbose, --quiet, --all, --long, etc).
```sh
# @flag --flag1 A flag
# @flag -f --flag2 A flag with short alias
```
### @alias
```
@alias <name...>
```
Add aliases for subcommand.
```sh
# @cmd Run tests
# @alias t,tst
test() {
echo Run test
}
```
```
USAGE: test.sh <COMMAND>
COMMANDS:
test Run tests [aliases: t, tst]
```
### @help
```
@help string
```
Enable help subcommand.
```sh
# @help Show help
# @cmd Run test
test() {
echo Run test
}
```
```
USAGE: test.sh <COMMAND>
COMMANDS:
help Show help
foo Run test
```
### Meta
- @describe: Sets the cli’s description.
- @version: Sets cli's version.
- @author: Sets cli's author.
```sh
# @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
```
### 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>`: complete files in current directory
- `<DIR>`: complete directories in current directory
- `<PATH>`: complete files and directories in current directory
## Shell Completion
[completion scripts](completions) are available for bash/zsh/fish/powershell.
All argc scripts share the same completion function. To add completion to a argc script, simply add the script name to `$ARGC_SCRIPTS`.
## License
Copyright (c) 2022 argc-developers.
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.