Installed, just not linked - macos

Question

Note: I'm not so good at using shell.
I was trying to install Valgrind using brew on Yosemite.
brew install --HEAD valgrind
Towards the end, I got an error having to do with linking so when I tried to reinstall, I got:
Warning: valgrind-HEAD already installed, it's just not linked
So apparently I've already installed it. Then based on other SO questions and answers, I tried:
brew link valgrind
This seemed to solve other people's problems with linking an already installed software but this gave me an error:
Linking /usr/local/Cellar/valgrind/HEAD...
Error: Could not symlink lib/pkgconfig/valgrind.pc
/usr/local/lib/pkgconfig is not writable.
I also tried to update brew but it didn't solve the issue. If it is not writable, maybe sudo would give me permission but I don't want to use sudo without knowing exactly what I am doing.
What is happening and how to I fix it?

Answer 1

Looks like a permission issue. I would try doing this
chmod 755 /usr/local/lib/pkgconfig
This should make that available, then try
brew link valgrind
If that doesn't work I would try doing a check on it
brew doctor

Answer 2

First run
brew link <package>
If it gives an error, try for an automated diagnosis
brew doctor
brew doctor gives a list of problems that could be leading to errors in installation process.
To fix problems in case of conflicting files,
run to get a list of all actions which will be performed by overwrite without actually performing them.
To list all files that would be deleted:
brew link --overwrite --dry-run <package>
followed by this run which will execute the overwrite, assuming you feel that the actions performed by overwrite will take your system to a more stable state.
To force the link and overwrite all conflicting files:
brew link --overwrite <package>

Answer 3

If none of above the solution works, try this.
sudo chown -R $USER:admin /usr/local
brew link <package-name>

Answer 4

In my case, brew doctor got it right. At some point /usr/local/lib/pkgconfig was set to be owned by root rather than my account. The prescribed remedy worked -
sudo chown -R $(whoami) /usr/local/lib/pkgconfig

Answer 5

I had same problem and i resolved with next solution:
Run brew doctor from Terminal to check all your errors
then run next command:
sudo chown -R $USER:admin /usr/local/bin /usr/local/etc /usr/local/sbin /usr/local/share
after run:
brew link <package_name>

Answer 6

Type
link valgrind
It will show an error that it can't be linked because such-and-such directory is not writable. Cool, we make it writable now. Type
sudo chmod a+w the/directory/shown/as/error
If the directory is not writable, you wont be able to change its permission and make it writable either. Sudo will make this operation possible. chmod will change the mode and will make all(a) users be able to write(w) it.
Next you will be prompted to type your system's password. After this, again type
link valgrind
and it will work this time.

Answer 7

Here is what I tried and it worked:
$ brew link --overwrite sdl
Linking /usr/local/Cellar/sdl/1.2.15...
Error: Could not symlink lib/pkgconfig/sdl.pc
/usr/local/lib/pkgconfig is not writable.
Looked for pkgconfig: (after chmod 750)
drwxr-xr-x 4 root wheel 136B Mar 30 2013 pkgconfig
I tried chown as below:
$ sudo chown -R avkashchauhan:admin /usr/local/lib/pkgconfig
it should look like as below:
drwxr-xr-x 4 avkashchauhan admin 136B Mar 30 2013 pkgconfig
After I tried it:
$ brew link sdl
Linking /usr/local/Cellar/sdl/1.2.15... 182 symlinks created

Answer 8

brew install cocoapods --build-from-source
brew link --overwrite cocoapods
The only commands that worked for me on after upgrading to MAC OS Mojave 10.14.6

Answer 9

I got a similar problem,
$ brew install sqlite
Updating Homebrew...
==> Auto-updated Homebrew!
Updated 1 tap (homebrew/core).
No changes to formulae.
Warning: sqlite-3.17.0 already installed, it's just not linked.
I tried to link it,
$ brew link sqlite
Warning: sqlite is keg-only and must be linked with --force
Note that doing so can interfere with building software.
Then do it by force,
$ brew link --force sqlite
Linking /usr/local/Cellar/sqlite/3.17.0... 8 symlinks created

Answer 10

I had same a problem about permission, but after I give my permission, still error permission. And here I do, first:
brew unlink valgrind
and then,
brew link valgrind
hope this help.

Answer 11

I had the similar issue. I needed to brew link carthage.
But none of answers worked for me.
I've also seen the next error for any command I tried:
Error: Could not symlink .
/usr/local/opt is not writable
Only one solution helped:
Open the Finder;
Command + Shift + G;
Pass the /usr/local path;
Create opt folder manually (that was the folder name from my error message, but in your case it can be something different, such as lib/pkgconfig in the original question, so check yours in the Terminal);
re-run your command again.