centos / linux automatically updates the network time

Install ntpdate

yum -y install ntpdate

　　

View current time

date

　　

Synchronize the current time

ntpdate time.nist.gov; #update time 
hwclock -w; #write time to hard disk

　　

Join a scheduled task

1. Open crontab 
vi / etc / crontab 

2. Add a scheduled task 
 * * / 48 * * * ntpdate time.nist.gov; hwclock -w;