From Han Wiki

Installation issue on OS X

  • Last tested on OS X El Capitan 10.11.5

When following the instruction for the installation of Compass website you get an error message.

$ sudo gem install compass
ERROR:  While executing gem ... (Errno::EPERM)
    Operation not permitted - /usr/bin/sass

OS X El Capitan does not allow write access to /usr/bin in spite of the sudo command. The recommended installation target folder is /usr/local/bin. We specify this path in the installation command.

$ sudo gem install -n /usr/local/bin compass