gem install sass
But, I get this error.
Fetching: rb-fsevent-0.10.2.gem (100%)
Successfully installed rb-fsevent-0.10.2 Fetching: ffi-1.9.18.gem (100%) Building native extensions. This could take a while... /usr/lib/ruby/2.3.0/rubygems/ext/builder.rb:76: warning: Insecure world writable dir /opt in PATH, mode 040777 ERROR: Error installing sass: ERROR: Failed to build gem native extension.
current directory: /var/lib/gems/2.3.0/gems/ffi-1.9.18/ext/ffi_c
/usr/bin/ruby2.3 -r ./siteconf20171018-24304-17ddhmp.rb extconf.rb mkmf.rb can't find header files for ruby at /usr/lib/ruby/include/ruby.h
extconf failed, exit code 1
Gem files will remain installed in /var/lib/gems/2.3.0/gems/ffi-1.9.18 for inspection. Results logged to /var/lib/gems/2.3.0/extensions/x86_64-linux/2.3.0/ffi-1.9.18/gem_make.out
what's wrong here? i installed Ruby stable release Ruby 2.4.2 Ruby stable release Ruby 2.4.2