I'm trying to install this: npm i -g gulp
But the output are these lines:
npm ERR! Darwin 16.3.0
npm ERR! argv "/usr/local/bin/node" "/usr/local/bin/npm" "install" "-g" "gulp"
npm ERR! node v7.4.0
npm ERR! npm  v4.0.5
npm ERR! path /usr/local/lib/node_modules
npm ERR! code EACCES
npm ERR! errno -13
npm ERR! syscall access
npm ERR! Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
npm ERR!  { Error: EACCES: permission denied, access '/usr/local/lib/node_modules'
npm ERR!   errno: -13,
npm ERR!   code: 'EACCES',
npm ERR!   syscall: 'access',
npm ERR!   path: '/usr/local/lib/node_modules' }
npm ERR! 
npm ERR! Please try running this command again as root/Administrator.
Just in case: when I ran npm root -g, I got the correct root folder: /usr/local/lib/node_modules
Please, how can I solve this? And install npm i -g gulp ??
Thanks!
 
    