How to add a CentOS user to the sudoers list

vi /etc/sudoers

...## Next comes the main part: which users can run what software on## which machines (the sudoers file can be shared between multiple## systems).## Syntax:####     user    MACHINE=COMMANDS#### The COMMANDS section may have other options added to it.#### Allow root to run any commands anywhere
root    ALL=(ALL)     ALL
youruser ALL=(ALL)  ALL

How to auto start services on boot in Centos / Redhat?

To auto start a new service:

• Find out the name of service’s script from /etc/init.d/ directory e.g. mysqld or httpd
• Add it to chkconfig
  sudo /sbin/chkconfig --add mysqld
• Make sure it is in the chkconfig.
  sudo /sbin/chkconfig --list mysqld
• Set it to autostart
  sudo /sbin/chkconfig mysqld on

To stop a service from auto starting on boot

• sudo /sbin/chkconfig mysqld off

防火墙开放80端口

[root@localhost lele]# /sbin/iptables -I INPUT -p tcp --dport 80 -j ACCEPT
[root@localhost lele]# /etc/rc.d/init.d/iptables save

如何修改centos等linux系统的hostname？重启后也生效

简单来说，uname -a 可以看到hostname，修改步骤如下：

1. uname -a 查看hostname
2. hostname www.ctohome.com 修改下，让hostname立刻生效。
3. vi /etc/hosts 修改原hostname为 www.ctohome.com
4. vi  /etc/sysconfig/network 修改原hostname为 www.ctohome.com,这样可以让reboot重启后也生效
5. reboot重启，uname -a 重新检查下。收工