So I’m a bit of a terminal noob so bear with me but I was trying to update brew to install something, so I ran: brew update and got Error: /usr/local must be writable!
Wasn’t really sure what that was about so I tried running sudo brew update and got sudo: effective uid is not 0, is sudo installed setuid root?
Not sure if this helps but running ls -l $(which sudo) gave me:
ls: is: No such file or directory ls: is: No such file or directory ls: is: No such file or directory ls: is: No such file or directory ls: sudo: No such file or directory ls: sudo: No such file or directory ls: sudo: No such file or directory ls: sudo: No such file or directory -r-s--x--x 1 root wheel 369136 Sep 13 20:56 /usr/bin/sudo -r-s--x--x 1 my_profile admin 168448 Jan 13 2016 /usr/local/bin/sudo -r-s--x--x 1 my_profile admin 168448 Jan 13 2016 /usr/local/bin/sudo -r-s--x--x 1 my_profile admin 168448 Jan 13 2016 /usr/local/bin/sudo
I tried the suggestion here (using Disk Utility and running First Aid) but it didn’t seem to have any effect….
Can anyone tell me what’s going on and what I need to do?
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Answer
If you run ls -la /usr, the result most likely will be something like below:
total 0
drwxr-xr-x@ 11 root wheel 374 Oct 14 14:35 .
drwxr-xr-x 32 root wheel 1156 Oct 26 09:49 ..
drwxr-xr-x 19 root wheel 646 Oct 10 18:51 local
... (some other files and directories)
Now it’s obvious from the above that unless you are logged in as a root or your user is in the wheel group (which is most likely not), any command you issue with your user which needs write permission (such as brew update) will fail.
One of the possible solutions (and I am not claiming is the best one) would be to change permissions of /usr/local.
Like so:
sudo chown -R $(whoami) /usr/local
Interestingly enough, if you then run
brew update
all goes well and you get the following message:
=> Migrating HOMEBREW_REPOSITORY (please wait)...
==> Migrated HOMEBREW_REPOSITORY to /usr/local/Homebrew!
Homebrew no longer needs to have ownership of /usr/local. If you wish you can
return /usr/local to its default ownership with:
sudo chown root:wheel /usr/local
Which I guess explains what happened in the first place.
Hope that helps.