centos yum

yum (Yellow dog Updater, Modified) is a software package manager. Redhat and Fedora's software installation command rpm (Redhat package Manager), but rpm is too much trouble to install the software you need to manually look for a series of dependencies required to install the software, in order to better manage package dependencies so Fedora introduced yum , can be a good software package and its dependencies to install and manage.
  yum will depend on the package and from the specified server to download, but yum default installation source server is foreign, domestic, then download speed will be very slow, it will usually yum install into a domestic source, such as Ali or 163. Yum will CentOS7 source was changed to the following steps Ali yum source.

    Install wget

    yum -y install wget
       

    back up the local yum source

    mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo_back
       

    download Ali yum source

    wget -O / etc / yum.repos.d / CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
       

    clean up cache yum

    yum clean all
       

    reconstruction cache

    yum makecache
       

    can update all the software systems using Ali yum source ( optional)

    yum -y Update
       

using EPEL extended warehouse

  Included in yum in just a few basic package, so if you want to download source yum package is not how to do? At this point, you can use EPEL extended warehouse. EPEL (Extra Packages for Enterprise Linux) is a set of high-quality enterprise-class Linux provides additional packages. Installation EPEL following steps:

    mounting-Release epel

    yum the install epel -Y-Release
       

    after installation can modify the original source EPEL Ali EPEL source

    backup epel original source

    mv /etc/yum.repos.d/epel.repo / etc /yum.repos.d/epel.repo_back
       
    Download Ali epel source

    wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo
       

    install yum source management tool

    yum install -y yum-priorities
       

    add yum and epel source priority source, the lower the number, the higher the priority
        open epel.repo file

    vi /etc/yum.repo.d/epel.repo
       

        add the following to the file and save the

    priority = 88
        . 1

        open file CentOS-Base.repo

    vi /etc/yum.repo.d/CentOS-Base.repo
       

        add the following to the file and save

    priority = 8
       

    open source yum priority feature

    vi /etc/yum/pluginconf.d/priorities.conf
       

        file should be
        [ main]
        Enabled =. 1

yum common commands are summarized

    yum syntax
    yum [-options] [command] [the packageName ...]
    -options is optional, commonly used are:

-options operation
-h display help information
-y prompted to select the entire installation process is "Yes"
-C specified configuration file
-q quiet mode (not show the installation process)
-v verbose mode
-R yum process a command setting the maximum waiting time
-C run from cache, or not to download any updates head file

    command for the operation to be carried out, commonly used are:

command operation
install install rpm package
update update rpm package
remove Removes the specified rpm package
list displays information package of
information search to check the package
info display descriptive information specified rpm packages and profiles
clean cleanup yum cache

    frequently used commands

    to list all updatable software inventory command:

        yum the Check-Update

    to update all the software and command All agreed Tip:

        yum -y update

    only install specific software commands and prompts all agree:

        yum -y install [packageName]

    only update the software specified in the order and agreed to all prompts:

        yum -y update [packageName]

    lists all installed software inventory command:

        yum list

    delete package commands:

        yum the remove [packageName]

    to find package command:

        yum Search [keyword]

    Clear cache command:
        Clear the cache directory under the package

        yum clean packages

        remove headers in the cache directory

        yum clean headers

        The old headers clear the cache directory

        yum clean oldheaders

        purge packages and old headers in the cache directory

        yum Clean All

wget command summary used

    wget syntax
    wget [-options] [URL Address]
    -options is optional, commonly used

-options operating
-O download saved to the specified path and file name
-c HTTP
-b background downloading
-P download saved to the specified directory
-d debug mode, open the debug output
-limit-rate speed download
-ftp-user --ftp -password user authentication using FTP download
-user-agent disguised proxy name download
-spider download link test

    commonly used commands

    using wget to download a single file, save the file to the current path

        wget [URL address]

    download and modify the save path and file name

        wget -O [save path and file name] [URL address]

    HTTP

        wget -c [URL address]

    Background downloading, use the tail -f wget-log file to view the download progress

        wget -b [URL address]

    speed download, the following command represents the maximum speed of 1KB / S

        wget -limit-Rate = 1K [the URL of address]

    saved to the specified directory

        wget [URL address] -P [directory address]

    test download links

        wget --spider [URL address]