I recently upgraded my Mac to High Sierra
After the upgrade, Macvim (mvim) stopped working because (I assume) HighSierra upgraded ruby to 2.3, and mvim
First find where is the right libruby path, mine is: /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/libruby.2.3.0.dylib
It is common that the version has changed.
Find out where the absolute path of vim is:
$ which vim
vim: aliased to your-path-of-vim
change dyld:
sudo install_name_tool -change /System/Library/Frameworks/Ruby.framework/Versions/2.0/usr/lib/libruby.2.0.0.dylib /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/libruby.2.3.0.dylib your-path-of-vim