Como posso instalair o terminal htpasswd através?

No terminal quando eu executo isso:

npm install -g htpasswd 

Eu recebo:

 checkPermissions Missing write access to /usr/local/lib/node_modules 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! stack: '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. 

Como eu conseguiria instalá-lo?