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Homebrew Command Not Found

This project reproduces Ubuntu’s command-not-found for Homebrew users on macOS.

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On Ubuntu, when you try to use a command that doesn’t exist locally but is available through a package, Bash will suggest you a command to install it. Using this script, you can replicate this feature on macOS:

# on Ubuntu
$ when
The program 'when' is currently not installed.  You can install it by typing:
sudo apt-get install when

# on macOS with Homebrew
$ when
The program 'when' is currently not installed. You can install it by typing:
  brew install when

Over 5000 formulae are supported, representing more than 17000 different commands (100% of the main Homebrew repo).


First, tap this repository:

brew tap homebrew/command-not-found
  • Bash and Zsh: Add the following line to your ~/.bash_profile (bash) or ~/.zshrc (zsh):

    HB_CNF_HANDLER="$(brew --repository)/Library/Taps/homebrew/homebrew-command-not-found/"
    if [ -f "$HB_CNF_HANDLER" ]; then
    source "$HB_CNF_HANDLER";
  • Fish: Add the following line to your ~/.config/fish/

    set HB_CNF_HANDLER (brew --repository)"/Library/Taps/homebrew/homebrew-command-not-found/"
    if test -f $HB_CNF_HANDLER
       source $HB_CNF_HANDLER


This tool requires one of the following:

  • Zsh (the default on macOS Catalina and above)
  • Bash (version 4 and higher)
  • Fish

How it works

When you tap the repo you’ll get two more brew commands: brew which-formula and brew which-update. The first one uses a database file which gives you the formula you have to install in order to get a specific command. The file is generated by the second command by crawling all installed formulae and collecting their binaries. Having this as a tap means you get an up-to-date binaries database each time you run brew update.

The script defines a command_not_found_handle function which is used by Bash when you try a command that doesn’t exist. The function calls brew which-formula on your command, and if it finds a match it’ll print it to you. If not, you’ll get an error as expected.