Cannot update brew in MAC OS X el capitan and keep getting a Load error with `require`

macos homebrew

I am not sure why this is happening but I cannot update brew in my MAC OS X El Capitan. I did:

brew update

and got:

warning: unable to unlink CONTRIBUTING.md: Permission denied
warning: unable to unlink SUPPORTERS.md: Permission denied
fatal: cannot create directory at '.github': Permission denied

to go over that issue I sudoed the above command but got further issues:

sudo brew update
Password:
/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- mach (LoadError)
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/local/Library/Homebrew/extend/pathname.rb:2:in `<top (required)>'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/local/Library/Homebrew/global.rb:3:in `<top (required)>'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/local/Library/brew.rb:16:in `<main>'

now whenever I do brew install I get:

brew update

/System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require': cannot load such file -- mach (LoadError)
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/local/Library/Homebrew/extend/pathname.rb:2:in `<top (required)>'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/local/Library/Homebrew/global.rb:3:in `<top (required)>'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/ruby/2.0.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /usr/local/Library/brew.rb:16:in `<main>'

in fact, it seems that whenever I do anything, like just type brew it gets the same message. Does anyone know how to fix this?

this is probably a super hacky solution but I completely uninstalled homebrew and re-installed it. To uninstall read: quora.com/How-does-one-uninstall-Homebrew

Possible duplicate of homebrew not working on OSX

Homebrew has been updated to address the problem of /usr/local ownership. If you haven't updated Homebrew in a while, follow the steps outlined by @bfontaine below. Once updated, you may revert ownership back to root:wheel by running sudo chown root:wheel /usr/local and, continue using and updating Homebrew without worrying about file ownership.

bfontaine

You shouldn’t use sudo with Homebrew. First run the following to ensure you own everything under /usr/local:

sudo chown -R $(whoami):admin /usr/local

Alternative command for newer macOS version:

sudo chown -R $(whoami) $(brew --prefix)/*

Then reset your Homebrew repo to a clean state:

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

It should fix your issues.

(replace /usr/local with $(brew --prefix) if you installed Homebrew elsewhere)

I ran sudo chown -R $(whoami):admin /usr/local but the terminal outputted nothing. What was I suppose to see?

Are you sure you really want to change ownership to a user in /usr/local? It seems very wrong to me even though it may work.

@CharlieParker unix filesystem layout -> en.wikipedia.org/wiki/Filesystem_Hierarchy_Standard.

I found this in the Homebrew FAQ in Github, which I think is relevant to this answer: "Why does Homebrew prefer I install to /usr/local?... 3. It’s safe Apple has left this directory for us. Which means there is no /usr/local directory by default, so there is no need to worry about messing up existing tools."

You may also need brew update after that to fix stuff.