parallel

name	parallel
description	Use this skill when the user wants to run commands in parallel, process multiple files simultaneously, or batch-process arguments with GNU parallel.

GNU parallel Plugin

Build and execute shell commands in parallel. Run commands on multiple files, CPUs, or hosts simultaneously.

Commands

Version

• parallel self version — Print GNU parallel version

Utility

• parallel _ _ — Passthrough to GNU parallel CLI

Usage Examples

• "Run multiple curl requests in parallel"
• "Process all these files with the same command"
• "Resize all images in parallel"
• "Run the same script on multiple inputs"

Installation

brew install parallel

Or via apt:

sudo apt-get install parallel

Examples

# Run commands in parallel from a file
parallel _ _ -a commands.txt

# Process all .txt files
parallel _ _ wc {} ::: *.txt

# Run gzip on all .log files with progress
parallel _ _ --progress gzip {} ::: *.log

# Convert all .png files to .jpg with 4 jobs
parallel _ _ -j4 convert {} {.}.jpg ::: *.png

# Run commands on remote hosts via SSH
parallel _ _ -S host1,host2 command ::: args

# Print version
parallel self version

# Show help
parallel _ _ --help

Key Features

• Job slots — Control parallelism with -j (e.g., -j4 for 4 jobs)
• Input sources — Files, stdin, command output, or ::: args
• Remote execution — Run on multiple SSH hosts with -S
• Progress display — --progress shows job completion status
• Result aggregation — --results saves output per job
• Error handling — --halt on error, fail, or success conditions
• Job log — --joblog for tracking job status and timing