Getting error on installing ionic

Hello guys,
if i run npm install -g ionic cordova.I’m getting below issue.

npm ERR! path /usr/local/bin/ionic

npm ERR! code EEXIST

npm ERR! Refusing to delete /usr/local/bin/ionic: …/lib/node_modules/ionic/bin/ionic symlink target is not controlled by npm /usr/local/lib/node_modules/ionic

npm ERR! File exists: /usr/local/bin/ionic

npm ERR! Move it away, and try again.