How to run sudo command without a password on a Linux or Unix

Posted on in Categories , , , , , , last updated April 18, 2017

I‘m a new Unix system user. How do I use sudo command without a password on a Linux or Unix-like systems? I log in as [email protected] and disabled root login for ssh. After login, I need to run some commands as root user. I am the only sysadmin using my server. How do I run or execute sudo command without a password for a user named Tom under Debian/Ubuntu/CentOS Linux cloud server?