thefuck — Magnificent Command Corrector for Your Terminal

Introduction

thefuck is a Python CLI app that listens for failed commands in your shell and proposes corrected alternatives. When you mistype a command, forget sudo, or use wrong flags, just type fuck and it will fix and re-run the command for you.

What thefuck Does

• Detects failed shell commands based on exit codes and stderr output
• Matches failures against a library of built-in correction rules
• Suggests the most likely corrected command automatically
• Supports custom user-defined rules for project-specific workflows
• Works across Bash, Zsh, Fish, PowerShell, and tcsh

Architecture Overview

thefuck intercepts the previous command's exit code and output via a shell alias. It then passes that context through a pipeline of rule matchers, each of which checks whether it can fix the error. Rules are plain Python modules with match() and get_new_command() functions. The highest-priority matching rule produces the corrected command, which is presented to the user or executed immediately based on configuration.

Self-Hosting & Configuration

• Install via pip: pip install thefuck or via Homebrew: brew install thefuck
• Initialize the alias in your shell profile with eval $(thefuck --alias)
• Configure settings in ~/.config/thefuck/settings.py (timeout, rules, priority)
• Set require_confirmation = False to auto-execute corrections without prompting
• Add custom rules as Python files in ~/.config/thefuck/rules/

Key Features

• Ships with 80+ built-in rules covering git, docker, pip, apt, cargo, and more
• Learns from your corrections and adjusts rule priority over time
• Supports instant mode for near-zero latency corrections
• Custom aliases let you rename the command to anything you prefer
• Extensible rule system with a simple two-function Python interface

Comparison with Similar Tools

• ShellCheck — static analysis for scripts; thefuck corrects interactive commands in real time
• zsh-autosuggestions — suggests from history; thefuck actively fixes failed commands
• fuck (Ruby) — earlier concept; thefuck has a much larger rule library and active maintenance
• pay-respects — Rust alternative with faster startup but fewer built-in rules

FAQ

Q: Does thefuck slow down my shell? A: In normal mode the alias only activates when you explicitly type the trigger. Instant mode adds a small hook but is designed to stay under 100ms.

Q: Can I use a different trigger word? A: Yes. Pass a custom name to the alias: eval $(thefuck --alias fix) and then type fix instead.

Q: Does it work with zsh and oh-my-zsh? A: Yes. There is also a bundled oh-my-zsh plugin for convenience.

Q: Is it safe to auto-run corrections? A: By default it asks for confirmation. You can enable auto-run, but review the rule list first to avoid surprises with destructive commands.

Sources

• https://github.com/nvbn/thefuck
• https://github.com/nvbn/thefuck#installation