When we install more than one operating system, we want to customize the default boot operating system, if we have finished installing CentOS, we need to modify the Gurb, the following is to modify the gurb operation:
1, log in as root.
2, check where the grub.conf (Grub configuration file) is. Enter in Terminal: Whereis grub.conf terminal output: "Grub:/sbin/grub/etc/grub.conf~/etc/grub.conf/usr/share/grub/usr/share/man/man8/ Grub.8.gz ", we can see that the directory of grub.conf is" etc ".
3, modify grub.conf. Open this file.
A, modify the default boot operating system.
We look at a few projects headed by "title", each of which is the operating system we install, and if we want to have a default boot operating system, we need to modify the value of "Default", which is set in array mode, The value set is the number of actual operating systems in our system-1, for example, we now have two operating systems, we want to set the first default operating system, then we should set this value to 0; If you want the second to be the default operating system, then you should set this value to 1.
B, modify the wait time.
Timeout is every time we boot the operating system, we wait, this time is seconds, we can modify the time we need.
After the above changes, save this file on it, the next time you start will install our settings to start.