pg_ctl: cannot be run as root Please log in (using, e.g., "su") 

Hi Dears,

I am trying to start the pgsql cluster in the ubuntu server by using the following command. but it's giving me the error mentioned in the subject. 
/usr/lib/postgresql/9.5/bin/pg_ctl -D /path/
I am using server image at a different host not at original one to restore DB, but unsuccessful.
please help.
thanks 