What is the best/safest way to reinstall Homebrew?

I am getting issues with permissions in Homebrew: After I installed Node and tried to install npm using the curl command Homebrew tells you to use, it would fail due to EACCESS errors. I checked the node folder and the permissions were a) unowned by a user (I had to chown it) and b) Had no write permissions (I had to chmod 755 it).

I've fixed the issue with NPM, but I had to run its install script as sudo (which is bad!).

I assume I must have installed Homebrew as root or something similar. I am hoping that reinstallation will fix it, but I can't find a source on how to reinstall Homebrew.

When I rerun the installer in Terminal I get:

/usr/local/.git already exists!

Update 10/11/2020 to reflect the latest brew changes.

Brew already provide a command to uninstall itself (this will remove everything you installed with Homebrew):

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall.sh)"

If you failed to run this command due to permission (like run as second user), run again with sudo

Then you can install again:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

Process is to clean up and then reinstall with the following commands:

rm -rf /usr/local/Cellar /usr/local/.git && brew cleanup
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install )"

Notes:

• Always check curl | bash (or ruby) commands before running them
• http://brew.sh/ (for installation notes)
• https://raw.githubusercontent.com/Homebrew/install/master/install (for clean up notes, see "Homebrew is already installed")

Try running the command brew doctor and let us know what sort of output you get

edit: And to answer the title question, this is from their FAQ :

> Homebrew doesn’t write files outside its prefix. So generally you can > just rm -rf the folder you installed it in.

So following that up with a clean re-install (following their latest recommended steps) should be your best bet.

For Mac OS X Mojave and above

To Uninstall Homebrew, run following command:

sudo ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"

To Install Homebrew, run following command:

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

And if you run into Permission denied issue, try running this command followed by install command again:

sudo chown -R $(whoami):admin /usr/local/* && sudo chmod -R g+rwx /usr/local/*

The way to reinstall Homebrew is completely remove it and start over. The Homebrew FAQ has a link to a shell script to uninstall homebrew.

If the only thing you've installed in /usr/local is homebrew itself, you can just rm -rf /usr/local/* /usr/local/.git to clear it out. But /usr/local/ is the standard Unix directory for all extra binaries, not just Homebrew, so you may have other things installed there. In that case uninstall_homebrew.sh is a better bet. It is careful to only remove homebrew's files and leave the rest alone.

For me, I need to do the below steps to re-install the brew from scratch.

sudo rm -rf /usr/local/Cellar/
brew cleanup
sudo rm -rf $(brew --repo)
/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

For me, this one worked without the sudo access.

ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

For more reference, please follow https://gist.github.com/mxcl/323731