Yum, as the name suggests, yellow Dog Updater, Modified. Yum has done the same work for RPM systems. It provides a simple command to automate the installation or updating of a software package, similar to the Apt-get tool under Debian, after installing and updating any other necessary packages first to meet the required package dependencies.
Characteristics of Yum:
Multiple resource pools can be configured at the same time (Repository)
Concise configuration file (/etc/yum.conf
automatically resolves the dependency problems encountered when adding or removing RPM packages
Easy to use
Maintain consistency with the RPM database
RHEL AS5 can upgrade the system's functionality through Yum, but the default Rhel-debuginfo.repo setting is to upgrade the system from Redhat yum Source, if you do not purchase Redhat services, REDHAT5 later version upgrade is charged, need key to upgrade, The use of Yum is not upgradeable. Fortunately, because CentOS is a free enterprise version, you can use the CentOS Yum source to update the Rhel AS5 system.
Configure Yum to update software from CENTOS5 source
[Root@clinet ~]# rpm--import http://ftp.twaren.net/Linux/CentOS/RPM-GPG-KEY-CentOS-5
Install the Ftp.twaren.net GPG, you can also add other resource pool, you choose a close to their own geographical point
[Root@clinet ~]# Rpm-qa gpg-pubkey*
Check GPG Key
Gpg-pubkey-e8562897-459f07a4
If you want to delete key, use the following command:
[Root@clinet ~]# rpm-e gpg-pubkey-e8562897-459f07a4
[Root@clinet ~]# Vi/etc/yum.repos.d/rhel-debuginfo.repo
[Rhel-debuginfo]
name=red Hat Enterprise Linux $releasever-$basearch-debug
baseurl=ftp://ftp.redhat.com/pub/redhat/linux/enterprise/$releasever/en/os/$basearch/debuginfo/
BaseURL is your yum source address.
Enabled=0
Whether to enable this warehouse, 1 is enabled, 0 is disabled
Gpgcheck=1
Setting gpgcheck=1 will let yum check the GNUPG signature of each downloaded RPM. This is done because you need the appropriate GNUPG key to register with your RPM database. Can prevent being deceived, such as: illegal intrusion release website, Trojan import package, so that uninformed users download
Gpgkey=file:///etc/pki/rpm-gpg/rpm-gpg-key-redhat-release
Gpgkey Address of the store
This is the default, copy add the following update point to insert into the Rhel-debuginfo.repo text behind
[Base]
name=red Hat Enterprise Linux $releasever-base
baseurl=http://ftp.twaren.net/linux/centos/5/os/$basearch/
Gpgcheck=1
[UPDATE]
name=red Hat Enterprise Linux $releasever-updates
baseurl=http://ftp.twaren.net/linux/centos/5/updates/$basearch/
Gpgcheck=1
[Extras]
name=red Hat Enterprise Linux $releasever-extras
baseurl=http://ftp.twaren.net/linux/centos/5/extras/$basearch/
Gpgcheck=1
[Addons]
name=red Hat Enterprise Linux $releasever-addons
baseurl=http://ftp.twaren.net/linux/centos/5/addons/$basearch/
Gpgcheck=1
[root@clinet ~] #yum Clean all erase cache and old packages
[Root@clinet ~]# yum install httpd test to update software