brew.rb Permission denied

Question

I was trying to brew update when I got suddenly a permission error:

/usr/local/bin/brew: line 28: /usr/local/Library/brew.rb: Permission denied /usr/local/bin/brew: line 28: exec: /usr/local/Library/brew.rb: cannot execute: Undefined error: 0

I also tried sudo brew update, but without any luck.

What can I do?

Answer 1

The way that worked for me was to do as @happylookout suggested.

cd /usr/local
git fetch origin
git reset --hard origin/master

However, you may get a permissions error such as:

error: unable to unlink old 'bin/brew' (Permission denied)
error: unable to unlink old 'share/man/man1/brew.1' (Permission denied)
fatal: Could not reset index file to revision 'origin/master'.

To fix this, you need to run the last command above with sudo:

sudo git reset --hard origin/master

Now you should be able to run brew update without errors.