Cannot update HomeBrew: Permission denied I am trying to fix some brew doctor error but now after manually erased some files that brew doctor suggested I get the following error when trying to do a brew update :

error: cannot open .git/FETCH_HEAD: Permission denied

Error: Failed to update tap: homebrew/versions
Already up-to-date.
If you are using OSX High Sierra chown operation is not permitted in /usr/local/ in this case use:

sudo chown -R $(whoami) /usr/local/Homebrew/