help - Rust Distilled

The help Command

The help command is a fundamental tool available in almost every command-line interface (CLI) application. It provides users with guidance on how to use various commands and options within the CLI application. Understanding how to effectively use the help command can significantly enhance your ability to navigate and utilize CLI tools.

General Usage of the `help` Command

In most CLI applications, the help command can be invoked in the following ways:

Basic Help: Display a general help message that includes a list of available commands and a brief description of each.
```
command --help
command -h
```
Command-Specific Help: Display help information specific to a particular command, including its options and usage examples.
```
command subcommand --help
command subcommand -h
```
Option-Specific Help: In some applications, you can get detailed help about specific options or arguments.
```
command --help option
```

The help command is invaluable for both beginners and experienced users, as it provides quick access to documentation directly from the command line.

Using the `help` Command with Cargo

Cargo is the Rust package manager and build system. It provides a variety of commands for managing Rust projects, and like many CLI tools, it includes a help command to assist users.

Displaying General Help

To see a list of all available Cargo commands and a brief description of each, you can use:

cargo --help

cargo -h

This will output a list of commands such as build, run, test, and more, along with a short description of what each command does.

Here is view of the output

Rust's package manager

Usage: cargo [+toolchain] [OPTIONS] [COMMAND]
       cargo [+toolchain] [OPTIONS] -Zscript <MANIFEST_RS> [ARGS]...

Options:
  -V, --version             Print version info and exit
      --list                List installed commands
      --explain <CODE>      Provide a detailed explanation of a rustc error message

      --config <KEY=VALUE>  Override a configuration value
  -Z <FLAG>                 Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details
  -h, --help                Print help

Commands:
    build, b    Compile the current package
    check, c    Analyze the current package and report errors, but don't build object files

    ...         See all commands with --list

See 'cargo help <command>' for more information on a specific command.

Displaying Help for a Specific Command

If you want detailed information about a specific Cargo command, you can append the --help flag to that command. For example, to get help for the build command:

cargo build --help

cargo build -h

This will provide detailed information on how to use the build command, including available options and examples.

Example: Using the help Command with Cargo

Here’s an example to illustrate how to use the help command with Cargo. Suppose you want to learn more about the run command in Cargo. You would type:

cargo run --help

The output will include:

A description of what the run command does.
The syntax for using the run command.
A list of available options and flags.
Examples of how to use the run command.

Here is a shortened output from the previous command

Run a binary or example of the local package

Usage: cargo run [OPTIONS] [ARGS]...

Arguments:
  [ARGS]...  Arguments for the binary or example to run

Options:
      --ignore-rust-version   Ignore `rust-version` specification in packages
      --message-format <FMT>  Error format
  -v, --verbose...            Use verbose output (-vv very verbose/build.rs output)
  -q, --quiet                 Do not print cargo log messages
      --color <WHEN>          Coloring: auto, always, never
      --config <KEY=VALUE>    Override a configuration value
  -Z <FLAG>                   Unstable (nightly-only) flags to Cargo, see 'cargo -Z help' for details
  -h, --help                  Print help

Commonly Used Cargo Commands with help

Here are some commonly used Cargo commands along with how to access their help documentation:

Build: Compile the current project.
```
cargo build --help
```
Run: Build and execute the current project.
```
cargo run --help
```
Test: Run the tests for the current project.
```
cargo test --help
```
Doc: Build the documentation for the current project.
```
cargo doc --help
```
Clean: Remove the target directory, which contains the compiled artifacts.
```
cargo clean --help
```

Using the help command effectively can make working with Cargo much more manageable, providing you with the necessary information to execute commands correctly and efficiently.

Conclusion

The help command is a powerful feature available in most CLI applications, including Cargo. By using help, you can quickly access the information you need to utilize the full range of capabilities provided by Cargo, making your Rust development experience smoother and more productive. Remember to always start with --help when exploring new commands or options within Cargo to ensure you understand their functionality and usage.

Rust Distilled

General Usage of the help Command

Using the help Command with Cargo