Solution to centos password loss

Recently, centos was installed. I accidentally lost my password and couldn't get in. I checked the information and found the method. The test was successful.
Exist here, spare.

1. When the grub screen appears, use the up/down key to select the item that you usually start Linux, and then press the e key.
2. Use the up and down keys again to select the one you usually start Linux (similar to kernel/boot/vmlinuz-2.4.18-14 Ro root = label =/), and then press the e key

3. Modify the command line you see and add single. The result is as follows:
Kernel/vmlinuz-2.6.18-8.el5 single Ro root = label =/rhgb quiet
4. Press enter to return, and then press the B key to start, you can directly enter the Linux Command Line
5. # vi/etc/shadow
Delete the contents of the first line, that is, the content before "root" and "Next", in the line starting with "root,
The first line is similar
Root ::......
Save (SHIFT + Z)
(If it cannot be saved, it is a problem with the file attributes, so chmod 755/etc/shadow will be OK)
6. # restart reboot. the root password is blank.