linux-Rescue Mode

What are the operating levels of 1.Linux?

0: Turn off the machine

1: Single-user mode

2: Multi-user mode, Cannot use NFS service

3: Multi-user mode

4: Reserved

5: Graphical interface

6: Restart

Centos7 and CENTOS6 are not the same, you can use the following command to view:

[Email protected] ~]# ls-l/usr/lib/systemd/system/runlevel*target

lrwxrwxrwx. 1 root root 15 June 1 06:02/usr/lib/systemd/system/runlevel0.target-Poweroff.target

lrwxrwxrwx. 1 root root 13 June 1 06:02/usr/lib/systemd/system/runlevel1.target-Rescue.target

lrwxrwxrwx. 1 root root 17 June 1 06:02/usr/lib/systemd/system/runlevel2.target-Multi-user.target

lrwxrwxrwx. 1 root root 17 June 1 06:02/usr/lib/systemd/system/runlevel3.target-Multi-user.target

lrwxrwxrwx. 1 root root 17 June 1 06:02/usr/lib/systemd/system/runlevel4.target-Multi-user.target

lrwxrwxrwx. 1 root root 16 June 1 06:02/usr/lib/systemd/system/runlevel5.target-Graphical.target

lrwxrwxrwx. 1 root root 13 June 1 06:02/usr/lib/systemd/system/runlevel6.target-Reboot.target

If, how grub configures the password, cannot enter single-user mode, only through the way of the disc. Enter rescue mode.

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After selecting the disc to enter the system, there are three options to select a third troubleshoorting.

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Select the red arrow that, rescue mode recovery system, then enter, then enter

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After the carriage return, the interface appears:

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Select 1, continue continue, and then enter

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This time you find ls/mnt/sysimage/root/and normal ls/root content.

Description/mnt/sysimage equivalent to the normal system/root directory

Using commands

chroot/mnt/sysimage/

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To modify a password using the passwd command

passwd Root

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Restart the server to complete the password modification

linux-Rescue Mode