README.md

rust-parallel

Run commands in parallel and aggregate outputs. Async application using tokio.

Example commands and detailed manual.

Listed in Awesome Rust - utilities

Similar interface to GNU Parallel or xargs plus useful features:

• More than 10x faster than GNU Parallel in benchmarks
• Run commands from stdin, input files, or ::: arguments
• Automatic parallelism to all cpus, or configure manually
• Transform inputs with variables or regular expressions
• Prevent output interleaving
• Shell mode to run bash functions and commands
• TUI progress bar using indicatif
• Path cache
• Command timeouts
• Structured debug logging
• Dry run mode
• Configurable error handling

Contents:

• Installation
• Documents
• Tech Stack

Installation

Homebrew

With Homebrew installed, run

brew install rust-parallel

Pre-built release

1. Download a pre-built release from Github Releases for Linux, MacOS, or Windows.
2. Extract the executable and put it somewhere in your $PATH.

From Crates.io via Cargo

1. Install Rust

2. Install the latest version of this app from crates.io:

   $ cargo install rust-parallel   
   

The same cargo install rust-parallel command will also update to the latest version after initial installation.

Documents:

1. Examples - complete runnable commands to give an idea of overall features.
2. Manual - more detailed manual on how to use individual features.
3. Benchmarks
4. Output Interleaving - output interleaving in rust-parallel compared with other commands.

Tech Stack:

• anyhow used for application error handling to propogate and format fatal errors.
• clap command line argument parser.
• itertools using multi_cartesian_product to process ::: command line inputs.
• indicatif optional TUI progress bar.
• regex optional regular expression capture groups processing for -r/--regex option.
• tokio asynchronous runtime for rust. From tokio this app uses:
  • async / await functions (aka coroutines)
  • Singleton CommandLineArgs instance using tokio::sync::OnceCell.
  • Asynchronous command execution using tokio::process::Command
  • tokio::sync::Semaphore used to limit number of commands that run concurrently.
  • tokio::sync::mpsc::channel used to receive inputs from input task, and to send command outputs to an output writer task. To await command completions, use the elegant property that when all Senders are dropped the channel is closed.
• tracing structured debug and warning logs.
  • tracing::Instrument is used to provide structured debug logs.
• which used to resolve command paths for path cache.