How to sudo without password on CentOS Linux

I am a new CentOS Linux system adminstrator. How do I use sudo command without a password on a CentOS Linux systems? I log in as marlena@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 CentOS Linux 7 server. How do I run or execute sudo command without a password for a user named marlena under CentOS Linux cloud server?

The sudo (“superuser do”) is nothing but a tool for CentOS Linux systems to run commands as another user. Typically as a root user. You can delegate common tasks such as reboot the server or restart the Apache or make a backup using sudo for unprivileged users. By default, sudo needs that a user authenticates using a password before running a command on CentOS 7. Some times you may need to run a command with root privileges, but you do not want to type a password using sudo command. This is useful for scripting or any other purpose. This can be achieved by editing /etc/sudoers file and setting up correct entries. You need to consider any security consequence of allowing a sudo command execute without a password on a CentOS 6 or 7.

Run sudo without password on CentOS Linux

  1. Backup /etc/sudoers file, run:
    sudo cp /etc/sudoers /root/sudoers.bak
  2. Edit the /etc/sudoers file on CentOS:
    sudo visudo
  3. Run /usr/sbin/rebootcommand without password on CentOS:
    marlena ALL = NOPASSWD: /usr/bin/reboot
  4. Save and exit the file.

How to execute ALL sudo commands without password on CentOS

Type the following command as root user:
# visudo
$ sudo visudo
Append the following entry to run ALL command without a password for a user named marlena:


Save and close the file in vim. It is also possible to grant access to the group name such as sysadm. Any member of sysadm group can run command without a password. The syntax is


Of course, you can force the sysadm group to run only given commands such as /usr/sbin/reboot and systemctl:

%sysadm ALL=(ALL) NOPASSWD: /usr/sbin/reboot, systemctl

Here is my sample config file:


You learned how to run ‘sudo’ command without entering a password in CentOS Linux using various configuration options. For more information see sudo command man page here.

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