Yum in Linux is the abbreviation of Yellow dog Updater Modified; the purpose of yum is to automatically upgrade, install and remove rpm packages, collect information about rpm packages, check dependencies and automatically prompt users to solve them.

#The operating environment of this tutorial: linux5.9.8 system, Dell G3 computer.

What is yum in Linux? How to configure? how to use?

yum is the abbreviation of Yellow dog Updater Modified. It was originally developed by yellow dog developer Terra Soft. Written in python, it was still called yup (yellow dog updater) at that time. It was later improved by the Linux@Duke development team at Duke University, hence the name.

The purpose of yum is to automatically upgrade, install/remove rpm packages, collect information about rpm packages, check dependencies and automatically prompt users to solve them.

The key to yum is to have a reliable repository. As the name suggests, this is a software warehouse. It can be an http or ftp site, or it can be a local software pool, but Must include the rpm header. The header includes various information about the rpm package, including description, functions, provided files, dependencies, etc. It is by collecting these headers and analyzing them that the remaining tasks can be completed automatically. .

It can automatically download and install RPM packages from a designated server. It can automatically handle dependencies and install all dependent software packages at once, without the need to download and install them again and again. You can also make a yum server yourself, and you can make a yum server based on the CD image.

Build a yum server:

(1) Local yum (the server cannot access the Internet)

The first step : Mount the CD first

mount?/dev/cdrom?/media/
echo?"/dev/cdrom??/media?iso9660?defaults?0?0"?>>?/etc/fstab?實現(xiàn)開機掛載

Step 2: Create a yum warehouse (take centos as an example)

vim /etc/yum.repos.d/iso.repo (iso is Get the name at will, but it must end with repo)

[Centos]
name=CentOS
baseurl=file:///media/??
gpgcheck=1
enabled=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6

Then save and exit

(if it is a redhat5.x system, write file:///media/Server/ here, It is the system of redhat6.x file:///media/Packages/)

Explanation of parameters

#####
[Centos]?????????????????????????（這個是一個標識，可以隨便取，必須唯一）
name=CentOS??????????????????????（這個是一個名字，可以隨便取，必須唯一）
baseurl=file:///media/Server/????（本地的路徑）??
enabled=1????????????????????????（為1則是打開倉庫，為0則是關閉倉庫）
gpgcheck=1???????????????????????（公鑰值）
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6?（檢測公鑰值的文件路徑）
[?]內的是倉庫的名字
name是倉庫的描述也可以說是名字
baseurl?倉庫的位置
enabled?是否啟用這個倉庫，1為起用，0為禁用
gpgcheck?是否檢查GPG簽名（用來驗證要安裝的包是不是REDHAT官方的）
gpgcheck?的存放地址我們需要用下面的命令導入這個簽名。才能使用這項功能
#####

After building yum, first enter

yum clean all

(2) External network yum (the server can access the Internet)

vim /etc/yum.repos.d/163.repo

[base]
name=centos6
baseurl=http://mirrors.163.com/centos/$releasever/os/$basearch
gpgecheck=1
gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-6

Then save and exit

If the system is 5.x version of redhat (baseurl=http://mirrors.163.com/centos/5/os/$basearch)

When installing yum on the external network, you can go to this website first and have a look
http://mirrors.163.com/

Use yum

First use yum to upgrade the software. Most yum operations require superuser permissions. Of course, you can use sudo.

It is common to add and delete software after installing the system. Yum can also be qualified for this task, as long as the software is installed by rpm.

The installation command is :

yum install xxx

yum will query the database to see if there is this software package. If there is, check its dependency conflict. If there is no dependency conflict, it is best to download and install it; if there is, a prompt will be given asking whether you want to install the dependency at the same time, or delete the conflicting package. You can make your own judgment.

The command to delete is :

yum remove xxx

Same as installation, yum will also query the database and give Tips for resolving dependencies.

Commonly used commands of yum:

1.yum?check-update????????列出所有可更新的軟件清單
2.yum?update?????????????安裝所有更新軟件
3.yum?-y?install?<package_name>?安裝指定的軟件
4.yum?update?<package_name>??更新指定的軟件
5.yum?list??<package_name>???????不加<package_name>列出所有可安裝的軟件清單，加了列出指定的
6.yum?-y?remove?<package_name>?刪除軟件
7.yum?search?<package_name>???查找軟件???????
8.yum?list?installed???列出所有已安裝的軟件包
9.yum?list?extras????列出所有已安裝但不在?Yum?Repository?內的軟件包
10.yum?info?<package_name>??不加<package_name>列出所有軟件包的信息，加了列出指定的?
11.yum?provides?<package_name>?列出軟件包提供哪些文件
12.yum?clean?packages?清除緩存目錄(/var/cache/yum)下的軟件包
13.?yum?clean?all?????清除緩存目錄(/var/cache/yum)下的軟件包及舊的headers

Recommended learning: "linux video tutorial"

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