wrapcli: Fake Command Identity With Ease

wrapcli is a Rust library that wraps an existing CLI tool and rewrites its output on the fly, making it appear as if a different tool produced the output.

Features

• Stream real-time output rewriting (line by line)
• Capture full output for post-processing
• Customizable rewriting rules
• Preserve original version information (optional)

Use Cases

• Create branded variants of CLI tools
• Mask internal tool names in user-facing output
• Add version information without changing the underlying tool
• Integrate legacy tools into modern workflows

Getting Started

Installation

Add wrapcli to your dependencies:

cargo add wrapcli

Basic Usage

use wrapcli::{run_streaming, WrapConfig};

fn main() -> std::io::Result<()> {
    let cfg = WrapConfig {
        orig_name: "rustc".into(),
        fake_name: "dustc".into(),
        fake_ver: "2.0.0".into(),
        save_orig: true,
    };

    let args: Vec<String> = std::env::args().skip(1).collect();
    let status = run_streaming(&cfg, args)?;
    std::process::exit(status.code().unwrap_or(1));
}

How It Works

When the wrapped tool outputs a line containing the original name, wrapcli intercepts it and applies rewriting rules:

1. The first occurrence of the original tool’s name and version is replaced with the fake name and fake version. If save_orig is true, the original version is appended in parentheses.
2. Any subsequent occurrences of the original name in usage lines are replaced with the fake name.

This ensures consistent output masking without breaking the tool’s functionality.

Configuration

The WrapConfig struct controls the rewriting behavior.

Fields

Example

#![allow(unused)]
fn main() {
use wrapcli::WrapConfig;

let cfg = WrapConfig {
    orig_name: "git".into(),
    fake_name: "gitter".into(),
    fake_ver: "3.0.0".into(),
    save_orig: false,
};
}

Examples

Streaming Output

use wrapcli::{run_streaming, WrapConfig};

fn main() -> std::io::Result<()> {
    let cfg = WrapConfig {
        orig_name: "cargo".into(),
        fake_name: "pargo".into(),
        fake_ver: "2.0.0".into(),
        save_orig: true,
    };

    let args = vec!["--version".to_string()];
    run_streaming(&cfg, args)?;
    Ok(())
}

Capturing Output

use wrapcli::{run_capture, WrapConfig};

fn main() -> std::io::Result<()> {
    let cfg = WrapConfig {
        orig_name: "rustc".into(),
        fake_name: "dustc".into(),
        fake_ver: "2.0.0".into(),
        save_orig: false,
    };

    let args = vec!["--version".to_string()];
    let result = run_capture(&cfg, args)?;
    
    println!("Captured stdout: {}", String::from_utf8_lossy(&result.stdout));
    println!("Captured stderr: {}", String::from_utf8_lossy(&result.stderr));
    Ok(())
}

Real-World Example: Wrapping Git

use wrapcli::{run_streaming, WrapConfig};
use std::env;

fn main() -> std::io::Result<()> {
    let cfg = WrapConfig {
        orig_name: "git".into(),
        fake_name: "gitter".into(),
        fake_ver: "3.0.0".into(),
        save_orig: true,
    };

    let args: Vec<String> = env::args().skip(1).collect();
    run_streaming(&cfg, args)
}

Links

crates.io docs.rs