Shulou(Shulou.com)06/03 Report--

Linux system network configuration

Test network connectivity: ping 223.5.5.5

First mileage: modify the address information of the network card

Use system commands to modify nmtui

Second mileage: restart the network card service

Centos7: systemctl restart network

Centos6: / etc/init.d/network restart

PS: in the enterprise environment, the network card cannot be restarted casually.

Ifdown enh0 & & ifup eth continuous action

PS: all configurations in the linux system can take effect. Related services must be restarted.

Third mileage: check to make sure that the network card is configured correctly

Address (mask) information configuration:

Centos7: ip address show

Centos6: ifconfig

How to check gateway information:

Centos7: ip route show

Centos6: route-n

PS: all operations must be checked during operation and maintenance

Fourth mileage: modify the gateway settings in the virtual network editor

Vmnet8 (nat)-- nat Settings-- Gateway Settings-- 10.0.0.254

Remotely connect to the Linux operating system

1) install and deploy remote software: xshell

2) Security software configuration process:-

3) establish remote connection configuration:

Address: remote host IP address

Protocol: there are many service names in the host = = project name ssh

Port: service number information in the host = = 22

4) errors often occur in remote connections / how to troubleshoot remote connection problems

Three steps for investigation

1) check whether the remote connection link is unblocked

Ping 10.0.0.200

Analyze the reasons:

An incorrect configuration of Nic address information nmtui

B Virtual software network configuration is incorrect

C the address of the virtual network card is not configured correctly

D re-restore the virtual network configuration

E check whether the virtual service in the system opens the win window properly + rmurf-run window-- services.msc-- Service-- vmware

2) system firewall service linux system firewall / windows firewall

3) SSH remote service is not enabled

Telnet 10.0.0.200 22

Directory structure of the system: everything starts from the root

Use an absolute path to find data: look for data information from the root

Features: better accuracy

C:\ oldboy01\ oldboy02\ oldboy03\ oldboy.txt

C:\ oldboy\ oldboy01\ oldboy02\ oldboy03\ oldboy04\ oldboy.txt

Use relative paths to find data: find data information from the current path

Features: it is more convenient to find data

Oldboy03/oldboy.txt

C:\ oldboy\ oldboy01\ oldboy02\ oldboy03\ oldboy04\ return to the upper layer without seeing olddog.txt

Master the system command prompt

Function: prompt managers to enter commands

[root@oldboyedu ~] #

01 02 03

Composition: consists of three parts: the host name information of the user information system logged in to the system displays the syntax format of the current directory information command

Command space parameter space data information (path / file)

Rm-f oldboy.txt system management basic commands:

A system runs related management commands

Restart the system:

Restart the system, restart in a few minutes

[root@oldboyedu ~] # shutdown-r 5 (minutes)

Shutdown scheduled for Tue 2019-09-03 04:49:30 EDT, use 'shutdown-c' to cancel.

The shutdown system plan will be executed at about 04:49:30 seconds in 2019-09-03. Use 'shutdown-c' to cancel the plan.

Broadcast message from root@oldboyedu.com (Tue 2019-09-03 04:44:30 EDT):

Broadcast restart system message by root@oldboyedu.com

The system is going down for reboot at Tue 2019-09-03 04:49:30 EDT!

The system will restart at 04:49:30 on 2019-09-03.

Cancel restart operation

[root@oldboyedu] # shutdown-c

Broadcast message from root@oldboyedu.com (Tue 2019-09-03 04:50:45 EDT):

Broadcast cancel restart operation message by root@oldboyedu.com

The system shutdown has been cancelled at Tue 2019-09-03 04:51:45 EDT!

The system restart operation has been cancelled

Restart immediately

[root@oldboyedu] # shutdown-r now/0

Shut down the system:

Shut down the system and restart in a few minutes

[root@oldboyedu ~] # shutdown-h 5 (minutes)

Shutdown scheduled for Tue 2019-09-03 05:03:36 EDT, use 'shutdown-c' to cancel.

Broadcast message from root@oldboyedu.com (Tue 2019-09-03 04:58:36 EDT):

The system is going down for power-off at Tue 2019-09-03 05:03:36 EDT!

The system will be shut down at 05:03:36 on 2019-09-03

Shut down the system immediately

[root@oldboyedu] # shutdown-h now/0

B commands related to the system directory

1) create directory command make directory = > mkdir

Mkdir / oldboy/

[root@oldboyedu ~] # mkdir / oldboy/oldboy01/oldboy02/oldboy03

Mkdir: cannot create directory'/ oldboy/oldboy01/oldboy02/oldboy03': No such file or directory

Cannot create a directory; there is no such file or directory

Mkdir-p / oldboy/oldboy01/oldboy02/oldboy03 creates a multi-level directory

PS: when operating a command, when no message is generated, it is the best news.

2) confirm that the directory has been created list = > ls list to display system data information

[root@oldboyedu ~] # ls / oldboy/oldboy01/-lists the data information under the specified directory

Oldboy02

[root@oldboyedu ~] # ls-d / oldboy/oldboy01/-lists whether the specified directory exists

/ oldboy/oldboy01/

3) switch the directory path change directory = > cd

Change directories by absolute path: cd / oldboy/oldboy01/oldboy02/oldboy03

Switch directories by relative path: in the oldboy03 directory-- > cd oldboy04

Cd/cd ~: quickly return to the home directory of the system user

Cd.. Quickly return to the previous directory

Cd.. /.. Quickly return to the superior directory

Cd -: quickly return to the same directory as the last time

Quiz:

Create two multi-level directories

/ oldboy/oldboy01/oldboy02/oldboy03/oldboy04/

/ oldgirl/oldgirl01/oldgirl02/oldgirl03/oldgirl04/

Go to the / oldboy/oldboy01/oldboy02/oldboy03/oldboy04/ directory first

Excuse me: how to switch to the / oldgirl/oldgirl01/oldgirl02/oldgirl03/oldgirl04/ directory

Absolute path switch directory command: cd / oldgirl/oldgirl01/oldgirl02/oldgirl03/oldgirl04/

Relative path switch directory command: cd.. / oldgirl/oldgirl01/oldgirl02/oldgirl03/oldgirl04/

Conclusion:

There is a superior-subordinate relationship between the directory and the directory: using relative path switching, the operation is more efficient.

There is no superior-subordinate relationship between directory and directory: absolute path switching is adopted to make the operation more efficient.

4) View the current path print working directory (output current working directory)-- pwd

[root@oldboyedu oldboy03] # pwd

/ oldboy/oldboy01/oldboy02/oldboy03

C commands related to system files

1) create file information touch

Touch oldboy.txt

2) check whether the confirmation file is created successfully

[root@oldboyedu oldboy] # ls / oldboy

Oldboy oldboy01 oldboy.txt

[root@oldboyedu oldboy] # ls / oldboy/oldboy.txt

/ oldboy/oldboy.txt

[root@oldboyedu oldboy] # ls / oldboy/oldboy01.txt

Ls: cannot access / oldboy/oldboy01.txt: No such file or directory

3) how to view the contents of the file cat cat-look at the contents of the file

[root@oldboyedu oldboy] # cat oldboy.txt-viewing an empty file

[root@oldboyedu oldboy] # cat / etc/hosts

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4

:: 1 localhost localhost.localdomain localhost6 localhost6.localdomain6

4) Edit the contents of the file

The first method to edit the contents of a file: vi/vim (not in the default centos7) = = Edit the file

The vi command edits the file:

First mileage: open a file

Vi oldboy.txt

Second mileage: enter an editing mode

Enter the lowercase letter "I"-- enter insert mode insert mode-> start editing the contents of the file

Third mileage: exit editing mode

Enter the keyboard key "esc"

Fourth mileage: save exit / do not save exit

: wq-write (write = = save) quit (exit)

Q-without editing, quit directly

: Q!-the content of the file has been modified and forced to exit

Common problems in vi editing: when the edited file is located in a directory that can only be edited, and cannot be edited in a directory, when the system cannot recognize the Chinese symbol information to edit the file, the name of the file to be edited must be specified after the vi command

The second method of editing the contents of the file: echo = = output the information to the screen

[root@oldboyedu oldboy] # echo "hello world"

Hello world

[root@oldboyedu oldboy] # echo "hello world" > / oldboy/oldboy.txt

[root@oldboyedu oldboy] # cat / oldboy/oldboy.txt

Hello world

File directories are related to some commands system data information for backup copy = > cp copy command

Syntax format: cp parameter source file (backup file required) destination file (file after backup)

Backup file information

Cp / etc/hosts / etc/hosts.bak

Cp / etc/hosts / opt/

Overwrite file problem

If you copy a file normally, you will be prompted to overwrite:

[root@oldboyedu ~] # cp / etc/hosts / opt/

Cp: overwrite'/ opt/hosts'? Y

[root@oldboyedu ~] # cat / opt/hosts

127.0.0.1 localhost localhost.localdomain localhost4 localhost4.localdomain4

:: 1 localhost localhost.localdomain localhost6 localhost6.localdomain6

Oldboy

How to force an override:

Method 1:\ cp oldboy01.txt / opt/-ignore the override prompt

Method 2: / usr/bin/cp oldboy01.txt / opt/-ignore the override prompt (still works)

Backup directory information

Cp-r / oldboy/ / tmp/ system data information move operation (cut) move = > mv

Syntax format: mv parameter source file (need to move file) destination path (to what path)

Move file information:

Mv oldboy01.txt / tmp/

Mobile directory information

Mv / oldboy/ / tmp/

Rename operation:

Mv oldboy/ oldgirl/

System data deletion command remove = = rm

Delete file information

Rm-f / oldboy/oldboy01.txt

Delete directory information

Rm-rf / oldboy/

-r Recursively delete the data under the directory

-f forcibly delete directory data information (no confirmation prompt)

Delete root operation:

Rm-rf-- no-preserve-root /

Rm-rf /

Important catalogs of the system

Bin-store command files (binaries) directory

Sbin-directories that superusers can save using the command

Etc-Storage system or service program profile information

Home-user data information is saved to the home directory of slum ordinary users

Root-user data information is saved to the Palace Super Admin root user home directory in the home directory

Mnt-temporary mount point directory

Opt-storing data information generated by third-party software programs

Usr/local

Proc-the data in the directory is stored in memory to store process information and kernel file information

Selinux-save selinux program configuration file information and system security related programs

Tmp-temporary storage data directory / Recycle Bin

Var-save files with frequent data changes (log files)

Official directory structure description: http://www.pathname.com/fhs/pub/fhs-2.3.html

System important file information:

/ etc/

1) Network card configuration file

Configuration file save path: / etc/sysconfig/network-scripts/ifcfg-eth0

Profile information description:

TYPE=Ethernet-define the type of network used

BOOTPROTO=none-whether the IP address can be obtained automatically the server is generally set to a fixed address

None/static: will not let the IP address change the enterprise environment

Dhcp: dynamic acquisition of IP addresses

NAME=eth0-set the Nic name information

DEVICE=eth0

UUID=f3a6f219-0d68-4e9b-b673-3b9205d05afb

-hardware identification number information

ONBOOT=yes-activate the system network card

IPADDR=10.0.0.200-configure IP address information

PREFIX=24-Subnet mask information determines how many hosts in a LAN can be configured with IP addresses

GATEWAY=10.0.0.254-configure gateway information to allow hosts to access the public network

DNS1=223.5.5.5-access domain name-- > ip address information

Visit the domain name of the website, and you can also show whether you can communicate.

Changes to the configuration file to restart the service:

Restart the network card service method 1: centos7

Systemctl restart network restarts all network cards

Restart the network card service mode 2: centos7 centos6

/ etc/init.d/network restart restarts all network cards

Restart the network card service mode 3: restart only the specified network card

Ifdown (interface down) eth0-stop eth0 network card

Ifup (interface up) eth0-start the eth0 network card

Ifdown eth0 & & ifup eth0-restart the specified eth0 network card

2) address Resolution Service profile

Configuration file save path: / etc/resolv.conf

Profile information description:

Nameserver 223.5.5.5

Supplement: common DNS servers

223.5.5.5 DNS 223.6.6.6 Aliyun *

114.114.114.114 Telecom operator DNS

8.8.8.8 Google DNS

Restart network services

The Nic DNS information will be overwritten / synchronized to the resolv.conf file

PS: the configuration information in the file, which will take effect immediately after the configuration is modified

3) Host name profile

Server system hostname naming guidelines:

Address name-computer room name-room cabinet

Bj-pbs-2012A

Sjz

Configuration file save path:

Centos7: / etc/hostname

Centos6: / etc/sysconfig/network

Permanent adjustment: the system must be restarted for the configuration to take effect

Vi / etc/hostname

Oldboy66-ZNB

Temporary adjustment: make the configuration take effect immediately (reconnect)

Hostname oldboy66-ZNB

Centos7 can be temporarily modified with permanent changes.

Hostnamectl set-hostname oldboyedu.com

4) the local resolution profile establishes a relationship between the host name and the IP address

Configuration file save path: / etc/hosts

5) realize automatic mounting of storage device files

Configuration file save path: / etc/fstab

Profile information description:

UUID=97630c81-c2f8-4735-9fe0-4d86e9aee1cd / xfs defaults 0 0

UUID=77c7cc12-e079-42f4-8462-2d76563eb7e5 / boot xfs defaults 0 0

UUID=ec4226e8-169c-4856-b114-30d19c21d82c swap swap defaults 0 0

01 02

01. UUID: hardware identification information = = Storage file information / dev/sda1: UUID= "77c7cc12-e079-42f4-8462-2d76563eb7e5"

/ dev/sda2: UUID= "ec4226e8-169c-4856-b114-30d19c21d82c"

/ dev/sda3: UUID= "97630c81-c2f8-4735-9fe0-4d86e9aee1cd"

6) realize the command file to run automatically when the system is booted.

Configuration file save path: / etc/rc.local (permission execution permission)

Profile information description:

How does the profile take effect:

Chmod + x / etc/rc.d/rc.local-add execution permissions to the configuration file

7) system variable or environment variable profile

Configuration file save path: / etc/profile-configuration variable / environment variable / configuration alias information?

Profile information description:

Method 1:

Vi / etc/profile

Last line: export PATH=$PATH:/tmp

Method 2:

Echo export PATH=$PATH:/tmp > > / etc/profile

PS: in an enterprise environment, adding information to a configuration file, adding information using echo must use > > append information

To make the configuration file effective:

Method 1: reconnect to the server

Method 2: use the command to load the environment variable configuration file immediately

Source / etc/profile

What are variables: use variables in script files to modify script contents flexibly

Set variable: format: variable name = variable value x+y=10 x value 5 y?

Name=oldboy

Call variable: echo $name

Script configuration:

[root@oldboy66 ~] # cat test.sh

Name=olddog

Echo $name 01

Echo $name 02

Echo $name 03

What are environment variables:

1) variables set in system mode

2) system variable names are all uppercase letters

How to modify an environment variable: PATH

Temporary modification:

Export PATH=$PATH:/tmp

Permanent modification:

Modify the configuration file: / etc/profile

The process of executing the principle of the command:

1) execute the command

2) load the system environment variable $PATH-- > / usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin

3) enter the directory specified by the environment variable

/ usr/local/sbin

/ usr/local/bin

/ usr/sbin

/ usr/bin

/ root/bin

/ tmp

4) there are corresponding command files in the specified environment directory-- > execute command operations

4) there is no response command file in the specified environment directory-- > command not found / No such file or directory

Common shortcuts:

Ctrl+a-quickly move the cursor to the beginning of the line

Ctrl+e-quickly move the cursor to the end of the line

Ctrl+ ← →-move the cursor quickly left and right according to the word string

Ctrl+w-delete (cut) a contiguous string of information (no space division)

Ctrl+y-paste cut information

Ctrl+u-delete (cut) all string information to the left of the cursor location

Ctrl+k-delete (cut) all string information to the right of the cursor location

Tips for using the vi command:

The skill of moving the cursor quickly

G/shift+g-quickly switch the cursor to the last line

Gg-quickly switch the cursor to the beginning of the file line

10gg-switches the cursor to the specified line

$- quickly switch the cursor to the end of a line

0 / ^-quickly switch the cursor to the beginning of a line

Quickly move the cursor and enter the editing state:

O-place the cursor on a new line below the current line and enter the editing state

O-place the cursor on a new line over the current line and enter the editing state

I-enter the editing state directly at the current position of the cursor

I-switch the cursor to the beginning of a line and enter the editing state

A-switch the cursor to the end of a line and enter the editing state

A-the next character in the current position of the cursor enters the editing state.

C-clear all the content to the right of the cursor and enter the editing state

Cc-clear the entire line and enter the editing state

Quickly edit file content information

Yy-copy the specified content information

Nyy-copy multiple lines of information

P-paste copied or cut information

3p-paste the copied or cut content 3 times

Dd-delete (cut) specify a line of information

Ndd-delete (cut) specify multiple lines of information

DG-delete everything after the line of the cursor (cut)

R-replace the character information where the specified cursor is located

R-enter into replacement mode, you can replace multiple character information

Bottom line function instruction

: set nu-displays file line number information

: set nonu-cancels the display of file line number information

: s/oldboy/oldgirl/-replace the information about the location of the cursor

:% s/oldboy/oldgirl/-replace all specified contents in the file

: 7recover12sUniverse /-replaces the specified line information

: 6 replacements: Oldboyax /-replace the specified line to the last line of the specified content

: 6 the match found in the line is replaced by all the information retrieved in the line.

: 6. Replace the first matching information retrieved in a row.

PS: when the replacement instruction is used, the split symbol can be used / # @

/ searched information-retrieve and filter specified information in the file

N means to retrieve the next matching information

N means to return to the previous matching information

/ searched information\ c-ignore case when retrieving information in files

Special operation skills

U-- undo-undo operation in vi editing

Ctrl+r-- redo-cancel the undo operation in vi editing

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