visudo command HowTo - Linux / Unix Q & A from nixCraft

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

in BASH Shell, CentOS, Debian / Ubuntu, FreeBSD, Linux, Suse, UNIX 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 tom@my-cloud-server-ip 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?

How To Add, Delete, and Grant Sudo Privileges to Users on a FreeBSD Server

in FreeBSD, UNIX, User Management last updated December 2, 2014

I‘m setting up a new FreeBSD server. I do not want to use a default root user who has full system access. How can I setup and grant sudo privileges to users on a FreeBSD VPS or server?

CentOS / Red Hat: Sudo Allows People In Group Admin To Run All Commands

in CentOS, Fedora Linux, Linux, RedHat and Friends, Security, Troubleshooting, Ubuntu Linux, User Management last updated August 18, 2009

I like the way Ubuntu Linux works – all people in admin groups should able to run all commands after running it via sudo “command-name”. How do I setup sudo under CentOS or Red Hat Enterprise Linux to allow all members of the ‘admin’ group to run all commands?

Sudo is Not Prompting For a Password When Re-executed Second Time

in BASH Shell, CentOS, Debian / Ubuntu, Fedora Linux, FreeBSD, HP-UX Unix, Linux, Mac OS X, OpenBSD, RedHat and Friends, Security, Solaris-Unix last updated May 2, 2012

I use sudo to provide permissions and command execution rights to other users under UNIX and Linux operating systems. However, I noticed something strange about sudo. When executing sudo, it will prompt for the user’s password the first time, but sudo no longer requires a password anymore when re-executing it. Why? Is this is a security risk?

sudo: Sorry, you must have a tty to run sudo Error on a Linux and Unix

in BASH Shell, Linux, Troubleshooting, UNIX last updated October 20, 2015

I‘m trying to run the following command:

ssh user@box.example.com sudo command1 /path/to/file

But, an error is displayed follows:

sudo: sorry, you must have a tty to run sudo

How do I fix this problem on Linux or Unix based systems?