Linux Patch auto-reboot

Patch script

# cat patch.sh
#!/bin/bash

echo
echo --------------------
echo
date
KERNEL=$(/bin/yum check-update | grep -i 'kernel.x86')
/bin/yum update -y

if [ "$KERNEL" = "" ]; then
  echo no kernel update;
  echo exit
  exit
else
  echo kerner update
  echo reboot
  /sbin/reboot
fi

echo

cron job

57 23 * * * /root/patch.sh 1>>/root/patch.log 2>&1