We can't create /var folder There is /private/var folder, but we can't create /var folder!
Why?

I'm using OS X El Capitan 10.11.5.
You can't create it because, /var is a symlink to /private/var.

&gt; ls -lha /var
lrwxr-xr-x@ 1 root  wheel    11B Jan 13  2016 /var -&gt; private/var