Date: Display time
Date-s "2015/05/21 14:46" modification time
Hwclock rinse into the clock inside
Cal Display Calendar
Ntpdate time.nist.gov Sync Internet time
Write synchronization time to Scheduled tasks:
echo "*/5 * * * * */usr/sbin/ntpdate time.nist.gov >dev/null 2>
&1 ">>/var/spool/cron/root
The wrong and correct outputs are put into the black hole >dev/null 2>&1
The following 3 methods are equivalent
/dev/null Empty Device black hole
1) 1>/dev/null 2>log/dev/null
2) * * * * * 1>/dev/null 2>&1
3) &>/dev/null
Crontab-l View Results
ETC/INIT.D/NTPD Start time synchronization software
Optimize the terminal timeout:
Export tmout=10 or tmout=10
Permanent modification: echo "Export tmout=10" >>/etc/profile
Entry into force: Source/etc/profile or. /etc/profile
Check in effect: Echo $TMOUT
Time synchronization introduction and optimization of terminal timeouts