Homebrew install permissions issue

Question

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/Cell         


        

Answer 1

Following the advice chukcha14 provided in his answer at There is no Cellar file in my usr/local dir for brew, I did this:

jaimes-mbp:SMR jaimemontoya$ brew install mongodb-community@4.2
Warning: You are using OS X 10.15.
We do not provide support for this pre-release version.
You may encounter build failures or other breakages.
Error: Could not create /usr/local/Cellar
Check you have permission to write to /usr/local
jaimes-mbp:SMR jaimemontoya$ sudo mkdir /usr/local/Cellar
Password:
jaimes-mbp:SMR jaimemontoya$ sudo chown $(whoami) /usr/local/Cellar
jaimes-mbp:SMR jaimemontoya$ brew install mongodb-community@4.2
Warning: You are using OS X 10.15.
We do not provide support for this pre-release version.
You may encounter build failures or other breakages.
==> Installing mongodb-community from mongodb/homebrew-brew
==> Downloading https://fastdl.mongodb.org/osx/mongodb-macos-x86_64-4.2.3.tgz
###################################################################################### 100.0%
Error: Failed to install plist file
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink .
/usr/local/opt is not writable.

You can try again using:
  brew link mongodb-community
Warning: The post-install step did not complete successfully
You can try again using `brew postinstall mongodb/brew/mongodb-community`
==> Caveats
To have launchd start mongodb/brew/mongodb-community at login:
  ln -sfv /usr/local/opt/mongodb-community/*.plist ~/Library/LaunchAgents
Then to load mongodb/brew/mongodb-community now:
  launchctl load ~/Library/LaunchAgents/homebrew.mxcl.mongodb-community.plist
Or, if you don't want/need launchctl, you can just run:
  mongod --config /usr/local/etc/mongod.conf
==> Summary