Error while installing Homebrew on Mac OS X (10.10.3): Unable to change file mode on /usr/local/
Solution 1:
From your ls output:
drwxr-xr-x 5 root wheel uchg 170 Aug 20 2015 local
That uchg flag means the file or directory cannot be changed. You can remove it with this command: sudo chflags -R nouchg /usr/local
For more information about file flags, see the man page for chflags: http://ss64.com/osx/chflags.html