Linux system Administrator Technology (Admin)-------Fourth day

??

?/etc:linux System Configuration File

Configure the following static address parameters for the virtual machine server

– Host Name: server0.example.com

? ? – IP Address: 172.25.0.11

???? – Subnet Mask: 255.255.255.0

– Default gateway: 172.25.0.254

[[Email protected] ~] #nmcli connection modify ' System eth0 '?

? ? ? ? ? ? ? ? Ipv4.method manual??????????? #手动配置参数????????

? ? ? ? ? ? ? ? Ipv4.addresses ' 172.25.0.11/24? 172.25.0.254 '

? ? ? ? ? ? ? ? Connection.autoconnect yes?????? #每次开机自动启用

3. Activating the network configuration

[[email protected] ~]# nmcli connection up ' System eth0 '

–dns Server: 172.25.254.254

[[Email protected] ~] #cat/etc/sysconfig/network-scripts/ifcfg-eth0------View network card information

[[Email protected] ~] #cat/etc/resolv.conf-------View DNS service information

Testing the DNS Resolution service

[[Email protected] ~] #nslookup server0.example.com?

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Building a yum Warehouse

[[Email protected] ~] #rm-rf/etc/yum.repos.d/*

[[Email protected] ~] #vim/etc/yum.repos.d/abc.repo

? ? ? "ABC"

???? name=abc

???? baseurl=http://172.25.254.254/content/rhel7.0/x86_64/dvd/

???? enbaled=1

???? gpgcheck=0

[email protected] ~]# Yum Clean all

[email protected] ~]# Yum repolist

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?? View Text File contents

? Cat?:? Suitable for viewing files with less content

? Less: good for viewing files with more content

Look at the text file part of the content

? ??

? ? ? Head?-n? :? first few lines

? ? ? Tail-n??: Tail Lines

?? View Time

?? date

?? calculator

?? BC

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Pipe: The output of the preceding command is processed by the following command as a parameter of the following command

? ? Display/etc/passwd text content 8--12 line?

[[email protected]/] #nl/etc/passwd or cat-n/etc/passwd-----Indicates the number of rows displayed

[Email protected]/]# HEAD-12/ETC/PASSWD | Tail-5-------Take out the first 12 lines and take the five elements out through the pipe.

[Email protected]/]# Cat-n/etc/passwd | head-12 | TAIL-5-----Front Plus line number, take the first 12 lines out, in the pipeline to take out the five elements

[Email protected]/]# Cat-n/etc/passwd | Less

[Email protected]/]# echo | BC----ECHO Print

[Email protected]/]# echo 8*8 | Bc

[Email protected]/]# ifconfig? | Head-2

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?? grep: View the contents of a text file, displaying the line containing the specified string

? ? ? –grep? [Options]? ' Match string '?? Text File ...

??

[[email protected]/]# grep ' root '?/etc/passwd------"grep" represents the meaning of the filter and takes the key fields out to view

[[email protected]/]# grep ' man '/etc/man_db.conf?

[[email protected]/]# grep ' root '/etc/passwd displays all the root-containing

[Email protected]/]# grep-i ' Root '?/etc/passwd? #忽略大小写

[[email protected]/]# grep ' root '?/etc/passwd

[Email protected]/]# grep-v ' root '/etc/passwd? #把不包含Root的行都显示出来

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? –^word? Start with a string word

–word$? End With string word

[[email protected]/]# grep ' ^root '/etc/passwd

[[email protected]/]# grep ' root$ '?/etc/passwd

[[email protected]/]# grep ' bash$ '?/etc/passwd

[[email protected]/]# grep ' ^$ '?/etc/default/useradd--------match blank lines to indicate a blank line in a text

[[email protected]/]# grep-v ' ^$ '?/etc/default/useradd------Remove empty lines so that blank lines no longer appear

???? Regular expression:? To express what you think in a descriptive language

? Remove comments and blank lines to show valid data:

? ? ? ? ? ? ? ? ? ? ? ? ? [[email protected]/] #grep-V ' ^# '/etc/login.defs? | ? grep-v ' ^$ '

##################################################### ? ? ?

Find Files by criteria

? Find the corresponding file recursively according to the preset conditions

–find? [catalogue]?? [Condition 1]?

– Common conditions indicate:

-type type (f file, D directory, L shortcut)

-name? " Document Name "

? ? -size +|-File Size (k, M, G)

-user? User name

[Email protected]/]# find/boot/?-type l

[[email protected]/]# ls/boot/grub/menu.lst----display content in short format

[[email protected]/]# ls-l/boot/grub/menu.lst---Display content in long format

[[email protected]/]# find? /boot/? -type? F Find all files in boot

[[email protected]/]# find? /boot/? -ty

PE? D

[[email protected]/]# find/etc/?-name "passwd" find the passwd in etc

[Email protected]/]# find/etc/?-name "*tab*"

[[email protected]/]# mkdir/root/install----mkdir Create a directory

[[email protected]/]# Touch/root/install.log---Touch to create a file?

[Email protected]/]# Touch/root/install.bak

[Email protected]/]# find/root-name "install*"

[Email protected]/]# find/root-name "install*"?-type D

[Email protected]/]# find/root-name "install*"?-type F

[Email protected]/]# find/boot/-size +10m

[Email protected]/]# find/boot/-size-10m

Use the--exec operation of the Find command-----(-exec)----equivalent to the ' | ' Pipeline Transportation

–find. .. -exec processing command {} \;

# find/boot/-size +10m

# find/boot/-size +10m? -exec? cp-r? {}?/opt/? \;

# ls?/opt?

# find/etc/?-name "*tab"

# find/etc/-name "*tab"?-exec cp-r? {}?/mnt/? \;

# LS?-a/mnt---Show all files including hidden files

##################################################

# Mkdir/root/findfiles

# Find/-user Student-type f-exec cp-r {}/root/findfiles/? \;-----Find student This user file and copy it into Root/findfiles

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? user and Group management

?

? User account:?

????????? 1. Can login the operating system??

????????? 2. Access control (different user rights are different)?

?

? Group accounts: Easy to manage user accounts (permissions)

? User account and group account unique identification:? Uid? Gid??

? The Administrator uid is: 0

?? Group account: Basic group?? Additional groups (public groups? Subordinate groups)

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? Using the Useradd command

–useradd [Options] ... User name

? Common Command Options

–-u User ID,-D home directory path,-s login shell

–-G Basic Group,-G additional Group

[[email protected]/]# ID NSD01

[Email protected]/]# grep ' nsd01 '/etc/passwd? #用户基本信息

Nsd01:x:1002:1002::/home/nsd01:/bin/bash

User name: Password placeholder: uid:gid: User's description: Home directory: Interpreter

[Email protected]/]# useradd? nsd01

[email protected]/]#? ID? nsd01?

[[email protected]/]# grep? ' NSD '?/etc/passwd?

[Email protected]/]# useradd-u 1100 nsd02?? #指定UID

[[email protected]/]# grep? ' NSD '?/etc/passwd?

[Email protected]/]# useradd-d/op/haha nsd03? #指定家目录

[[email protected]/]# grep? ' NSD '?/etc/passwd?

?? Specify the Login interpreter program

[Email protected]/]# useradd-s/sbin/nologin nsd04?

[[email protected]/]# grep? ' NSD '?/etc/passwd

?

? Cannot log on to the operating system if the user's interpreter program is/sbin/nologin

[Email protected]/]# useradd-g nsd01 nsd09

[[email protected]/]# ID nsd09

[Email protected]/]# useradd-g nsd01? nsd10

[[email protected]/]# ID NSD10

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? User password information stored in the/etc/shadow file

Using the passwd command

–passwd [user Name]

–echo ' password '?? | ? passwd?--stdin? User name

? Supplemental command: command to temporarily switch user identities

[[email protected]/]# su?-? user name

[Email protected]/]# echo 123 | passwd--stdin NSD01

[Email protected]/]# echo 123 | passwd--stdin nsd02

[email protected]/]# su?-? nsd01

[Email protected] ~]$ passwd?

[Email protected] ~]$ exit?????? #退回到root

[Email protected]/]#

####################################################

Modify User Properties

? Using the Usermod command

–usermod [Options] ... User name

? Common Command Options

–-u User ID,-D home directory path,-s login shell

–-G Basic Group,

–-g additional Groups

[Email protected]/]# Useradd nsd11

[[email protected]/]# grep ' nsd11 '/etc/passwd

# usermod-u 1200-d/opt/test?-s/sbin/nologin nsd11

[[email protected]/]# grep ' nsd11 '/etc/passwd

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Delete User

? Using the Userdel command

–userdel [-r]? user name? #并且删除家目录

? Common tip: Insufficient permissions

? Permission denied

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Group account Management

Add Group

???? Group basic information is stored in the/etc/group file

[Email protected] ~]# head-1/etc/group

root:x:0:

?

? Group name: Password placeholder: GID: Group member list

? Using the Groupadd command

–groupadd [-G group ID]? Group name

[Email protected] ~]# Useradd Kenji

[Email protected] ~]# Useradd Tom

[Email protected] ~]# Useradd Kaka

[Email protected] ~]# Useradd Henter

[Email protected] ~]# Groupadd? Tarena

[[email protected] ~]# grep ' Tarena '/etc/group

TARENA:X:1110:

?

Using the GPASSWD command

–GPASSWD-A user name? Group name

–gpasswd-d user name? Group name

–gpasswd-m ' user name, user name '? Group name? #可以添加多个

[Email protected] ~]# grep ' Tarena '/etc/group? #查看组信息

[Email protected] ~]# gpasswd-a Kenji Tarena? #加入组成员

[email protected] ~]# ID Kenji?

[Email protected] ~]# gpasswd-a Tom Tarena

[[email protected] ~]# grep ' Tarena '/etc/group

[Email protected] ~]# gpasswd-a Kaka Tarena

[[email protected] ~]# grep ' Tarena '/etc/group

[Email protected] ~]# gpasswd-d Kenji Tarena? #删除组成员

[[email protected] ~]# grep ' Tarena '/etc/group

[Email protected] ~]# gpasswd-m ' Kenji,henter ' Tarena

[[email protected] ~]# grep ' Tarena '/etc/group

[Email protected] ~]# gpasswd-m ' Kenji,kaka,tom,henter ' Tarena

[[email protected] ~]# grep ' Tarena '/etc/group

[Email protected] ~]# gpasswd-m? ' Tarena

[[email protected] ~]# grep ' Tarena '/etc/group

Delete a group

? Using the Groupdel command

–groupdel Group Name

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? Archiving and compression

? ? 1. Space saving

? ? 2. Facilitate the management of fragmented documents

? Tar Integrated Backup tool

–-c: Creating an Archive

–-x: Release Archive

–-f: Specify the archive file name

–-z,-j,-j: Calling the. gz,. bz2,. xz Format tools for processing

–-c (UPPERCASE): Specify the release location

–-t: Displays a list of files in the archive

–-p (uppercase): Keep the absolute path to the file within the archive

[Email protected] ~]# rm-rf/opt/*

[Email protected] ~]# rm-rf/mnt/*

# tar-zcf/opt/file.tar.gz/boot//ETC/PASSWD

[Email protected] ~]# ls/opt

[Email protected] ~]# tar-xf/opt/file.tar.gz?-c?/mnt

[Email protected] ~]# ls/mnt

[Email protected] ~]# ls/mnt/etc

[Email protected] ~]# Ls/mnt/boot

? Use tar-c ... Command

–tar-zcf? backup files. tar.gz? The document being backed up ....

–tar-jcf? backup files. tar.bz2? The document being backed up ....

–tar-jcf? backup files. tar.xz? The document being backed up ....

[[email protected] ~]# tar-tf/opt/file.tar.gz??

Use BZIP2 compression to package and compress in absolute path mode

# TAR-PJCF,/root/backup.tar.bz2?????/usr/local/

# ls?/root/

# TAR-TF,/root/backup.tar.bz2????? #查看包里面内容

? ? -Z? represents gzip compression format

? ? -j? represents bzip2 compression format

? ? -j? Represents the XZ compression format

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NTP Network Time Protocol

? Network Time Protocol

–NTP Server provides standard time for clients

–NTP client need to maintain communication with NTP server?

????? package, configuration, service?

? One, the server, the Linux system on a software

? ? NTP time synchronization server, classroom

? ?

? II. client server, installing client software

?

? RHEL7 Client's School Time service

– Package: Chrony

– Configuration file:/etc/chrony.conf

– System Services: Chronyd

[Email protected] ~]# rpm-q chrony

Chrony-1.29.1-1.el7.x86_64

[Email protected] ~]# vim?/etc/chrony.conf

? #server 0.rhel.pool.ntp.org iburst?? #注释

? #server 1.rhel.pool.ntp.org iburst?? #注释

? #server 2.rhel.pool.ntp.org iburst?? #注释

172.25.254.254 iburst????? #指定服务端IP地址

.......

[Email protected] ~]# systemctl restart? chronyd? #重起服务

[Email protected] ~]# systemctl? Enable Chronyd? #设置开机自起

? Verify:

[[Email protected] ~]# Date

[Email protected] ~]# date-s "2008-09-08 11:11:11"? #修改时间

[[Email protected] ~]# Date

[[email protected] ~]# systemctl restart chronyd #重起服务, sync

[[Email protected] ~]# Date

[[Email protected] ~]# Date

[[Email protected] ~]# Date

Linux system Administrator Technology (Admin)-------Fourth day