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

System important catalogue

/ etc/-Storage profile

/ bin/-storing command files (binaries) can be used by ordinary users

/ sbin/-storing command files (binaries) can be used by root users

/ home/-user home directory slum ordinary user home directory

/ root/-user home directory Imperial root user home directory

/ opt/-save software program data

/ var/-record log information

Important file information of the system

/ etc/

/ usr/-how to install the software (not included with the system)

/ var/-- messages secure

/ proc/-all the data in the directory is stored in memory

System important file information:

/ etc/

1) Network card configuration file

The path where the configuration file is saved is: / etc/sysconfig/network-scripts/ifcfg-eth0

Profile information description:

TYPE=Ethernet-defines the type of network used

BOOTPROTO=none-whether the IP address can be obtained automatically

None/static: will not let the IP address change

Dhcpd: dynamic acquisition of IP addresses

NAME-sets the Nic name information

DEVICE=eth0

ONBOOT=yes-activate the system network card

IPADDR=10.0.0.200-configure IP address information

PREFIX=24-Subnet mask information 255.255.255.0

Determine 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 display whether or not

Can communicate

1) change the configuration file to restart the service:

Restart the network card service mode 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 Nic service mode 3:

Ifdown (interface down) eth0-stop the eth0 network card

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

Infdown eth0 & & ifup eth0

(used together)

2) address Resolution Service profile

Configuration file save path: / etc/resolv.conf

Profile information description:

Nameserver 223.5.5.5

Supplement: common DNS servers

223.5.5.5Compact 223.6.6.6 offer: Aliyun DNS

114.114.114.114 offer: telecom operator DNS

8.8.8.8 available: Google DNS

Restart network services

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

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

3) Host name profile *

Server system hostname naming guidelines:

Area name-computer room name-room cabinet

Configuration file save path:

Centos7:/etc/hostname (change the name, you must restart the system to take effect)

Centos6:/etc/sysconfig/network

Temporary adjustment: let the configuration take effect immediately (reconnect) hostname + name

Centos7 can be temporarily modified with permanent changes.

Hostnamectl set-hostname + name

4) resolve the profile locally (establish a relationship between the host name and the IP address) *

Path to save the configuration file: / etc/hosts5) to automatically mount the storage device file *

Configuration file save path: / etc/hosts

Profile information description

① UUID== hardware identification information = = storage file information 6) to enable the system to issue automatic operation commands *

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

Extension: system scripts (special) make complex / repetitive work-> efficient and simple

How to script ①: for commands

② run script file: sh / path / script file modify script file permissions to execute permissions-/ path / script 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

Make the configuration file effective: method one: reproduce the connection server mode two: use the command to load the environment variable configuration file source / etc/profile immediately what is the variable: the script file uses the variable, the flexible use sets the variable: format: variable name = variable value x+y=10 xvariant 5 yearly? Name=oldboy call variable: echo $name script configuration: [root@oldboy66 ~] # cat test.sh name=olddog echo $name 01 echo $name 02 echo $name 03 what are environment variables: 1) variables set in system mode 2) system variables are capitalized how to modify environment variables: PATH temporary modification: export PATH=$PATH:/tmp permanent modification: modify configuration file : / etc/profile command execution principle process: 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 environment variable specified directory / usr/local/sbin / usr/local/bin / usr/sbin / usr/bin / root/bin / tmp 4) there is a corresponding command file in the specified environment directory-- > execute command operation 4) there is no response command file in the specified environment directory-- > command not found / No such file or directory

Job: how to automatically mount the CD-ROM drive (two ways)

Review how to operate soft and hard connections

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