Linux Learning notes the fourth session of the first week (January 25)

Fourth session of the Week (January 25)

1.13 Single-user mode         

(1) Single user mode purpose: RESET login password;         

(2) Enter single user mode                  

after the host has just turned on or restarted, press the keyboard "↑" or "↓" key, enter the system selection interface, press keyboard "↑" or "↓" key, choose CentOS Linux (3.10.0-514.e17.x86_64) 7 (Core), the installation system version is different, there are some differences; Select OK, press "E" key to enter the edit boot command;

First find "linux16" at the beginning of the line, and then find "Ro", will be replaced by the RO RW init=/sysroot/bin/sh

After the change, press "Ctrl+x" to start;

Enter the original system, command #chroot/sysroot

language is English ( if not set, display as garbled ), command #lang=en

Change Password, command #passwd root Enter new password, enter new password again

Create a. autorelabel file (and Selinu, if not created, the password does not take effect), command #touch/.autorelabel

Force restart, and then login to enter the latest password, you can complete the reset password.

1.14 Rescue Mode         

(1) Rescue mode purpose: Resetting the login password or repairing the system file error;         

(2) Rescue mode and single-user mode differences, rescue mode with CD-ROM, and in the case of not knowing the grub password;         

(3) Enter rescue mode                  

First put the Linux installation CD into the CD-ROM drive, power on, press the DELETE key to enter the BIOS, set the CD Boot

Select the Boot tab and move the CD-ROM drive first,

F10 button, save and exit  

after rebooting, go to the boot menu, keyboard "↑" or "↓" key Select troubleshooting, enter

Select Rescue a CentOS Linux system, enter, follow the prompts, and then enter

Enter 1, (1 means continue, 2 means read-only loading, 3 means skip shell,4 to exit), enter

Enter, English prompt command chroot/mnt/sysimage can enter the original host system

input command chroot/mnt/sysimage into the original system input

Change Password command passwd root or passwd, enter new password, confirm new password

Force restart the machine and remove the disc.

1.15 Cloning a virtual machine

menu bar, click Virtual Machine, dropdown list management, right list select clone, Next, Next, Clone method general Select Create Link clone (full clone takes up too much space, no need), next

Fill in the virtual machine name, browse the storage location, here default

Click Done, auto Generate,

To change the IP address, refer to the IP configuration to learn the note-taking method by clicking Close.

Change host name, command Hostnamectl set-hostname centos702

1.16 Linux machines log in to each other         

(1) Interconnect command SSH [email protected];                  

ssh-p Port If port connection is specified [email protected]                  

Description: SSH command for the system to bring, the user name may not be entered to indicate the current user, write only IP;  

(2) SSH key authentication                  

Generate Key command Ssh-keygen, enter, do not set a password enter, do not set the password enter,

Copy the public key and save it on the host that needs to be connected

Turn selinux off, command setenforce 0; connect ssh [email protected], no password login is successful.

Linux Learning notes the fourth session of the first week (January 25)