Recusively change the owner of files (chown) on Mac OS X

515439429

　　I've just changed my OS X / Mac main user - I've created a new 'coder' user account that I want to use for development instead of my old 'lombard' account. I realized that a lot of my applications I've previously installed via Homebrew now had to be changed to be owned by the new coder user. First I ran 'brew doctor' find see what obvious issues I have:

Gerts-Mac-mini:src coder$ brew doctor
Warning: /usr/local/etc isn't writable.
This can happen if you "sudo make install" software that isn't managed by
by Homebrew. If a brew tries to write a file to this directory, the
install will fail during the link step.
You should probably `chown` /usr/local/etc
xcode-select: note: no developer tools were found at '/Applications/Xcode.app', requesting install. Choose an option in the dialog to download the command line developer tools.
xcode-select: note: no developer tools were found at '/Applications/Xcode.app', requesting install. Choose an option in the dialog to download the command line developer tools.
Warning: You have an outdated version of /usr/bin/install_name_tool installed.
This will cause binary package installations to fail.
This can happen if you install osx-gcc-installer or RailsInstaller.
To restore it, you must reinstall OS X or restore the binary from
the OS packages.
Warning: Git could not be found in your PATH.
Homebrew uses Git for several internal functions, and some formulae use Git
checkouts instead of stable tarballs. You may want to install Git:
brew install git
Warning: No developer tools installed.
Install the Command Line Tools:
xcode-select --install
xcode-select: note: no developer tools were found at '/Applications/Xcode.app', requesting install. Choose an option in the dialog to download the command line developer tools.

　　Indeed, several files/directories below '/usr/local' were created by Homebrew as user 'lombard':

Gerts-Mac-mini:src coder$ ls -l /usr/local
total 80
-rw-r--r--   1 lombard  admin   3158  5 Jun 09:16 CODEOFCONDUCT.md
-rw-r--r--   1 lombard  admin    687  5 Jun 09:16 CONTRIBUTING.md
drwxr-xr-x   4 lombard  admin    136 17 Jun 17:11 Cellar
-rw-r--r--   1 lombard  admin   1253  5 Jun 09:16 LICENSE.txt
drwxr-xr-x   9 lombard  admin    306 17 Jun 17:11 Library
-rw-r--r--   1 lombard  admin   1858  5 Jun 09:16 README.md
-rw-r--r--   1 lombard  admin  23719  5 Jun 09:16 SUPPORTERS.md
drwxrwxr-x  12 root     admin    408 17 Jun 17:11 bin
drwxr-xr-x   3 lombard  admin    102 17 Jun 17:11 etc
drwxrwxr-x   5 root     admin    170 17 Jun 17:11 lib
drwxr-xr-x   3 root     wheel    102 17 Jun 17:11 libexec
drwxrwxr-x   4 root     admin    136 17 Jun 17:11 share

　　I can't just use 'chown -R' because I only want to change the owner of some specific files. To recursively fix/change the owner only of files specifically owned by another user, use the versatile 'find' command:

$ find . -user lombard -exec sudo ch
own coder {} \;

　　Now I just took care of the other things that brew doctor complained about:

$ xcode-select --install
$ brew update

　　That's it! Now I'm ready to install more tools using Homebrew using the new user account.