I have a standard homebrew install inside of usr/local/
When I try:
Larson-2:~ larson$ brew install postgresql
Error: Cannot write to /usr/local/Cellar
And when I use sudo:
Larson-2:~ larson$ sudo brew install postgresql
Cowardly refusing to `sudo brew install'
What am I doing wrong?
You somehow have limited permissions to /usr/local/Cellar. Brew doesn't like to install with sudo which is why it refuses.
Check the permissions:
ls -ld /usr/local/Cellar
Open them up for writing:
sudo chmod a+w /usr/local/Cellar
Do not use sudo when working with brew (for security reasons).
You've to simple set-up your permissions.
So I would go even further and change the permissions to:
sudo chgrp -R admin /usr/local /Library/Caches/Homebrew
sudo chmod -R g+w /usr/local /Library/Caches/Homebrew
and then apply the specific group (either admin or staff) to user which should be allowed to use brew command. Check groups of your user via: id -Gn).
If there are further issues, run: brew doctor to see what's wrong.
I'd change the group permissions:
$ chgrp -R admin /usr/local/Cellar
$ chmod g+w /usr/local/Cellar
assuming your user account is in group admin.
This also happens if you have multiple users on your machine. If so, it would be best for you to change the user since every other approach would have you messing around with a lot more files and folders than just /usr/local/Cellar
Use su userWhoInstalledBrew.
The problem can be solved by changing the directory's owner to the current user:
sudo chown -R $USER /usr/local
This answer is taken from: https://github.com/Homebrew/homebrew/issues/17884
来源：https://stackoverflow.com/questions/9800527/homebrew-install-permissions-issue