The use of Yum under Linux

Software upgrades are improvements to software functionality and security upgrades, similar to Windows systems, the Linux operating system also needs to update the software on a regular basis, keep the software always in the latest state. Linux operating system upgrades can be divided into automatic upgrades and manual upgrades in two ways: automatic upgrades under the authorized Linux distribution or free Linux distribution, as long as the input Upgrade command, the system will automatically complete the upgrade work without human intervention.

Yum is the abbreviation of Yellowdog Updater Modified, Yellow Dog (Yeller) is also a distribution of Linux, but Redhat company is to use this upgrade technology to its own distribution to form the current yum. Yum is a commonly used tool for Linux automatic upgrades, with the Yum tool and the Internet can be implemented automatically upgrade the system. For example, an authorized Redhat Linux operating system, or a CentOS Linux system, as long as your system can connect to the Internet, input yum Update can achieve automatic system upgrades. System upgrades through Yum is essentially a yum command to download the RPM package on the specified remote Internet host, and then automatically install it, while resolving the dependencies between the various software.

Manual upgrades are targeted for upgrading a system's software, such as the SSH login tool for the upgrade system, the GCC compilation tool, and so on. Manual upgrade is actually through the RPM package tool to implement software updates, so when upgrading software may encounter dependencies between the software, upgrade relatively troublesome.

The following specifically describes how to set up the Yum tool under the CentOS Linux4.4 for automatic system upgrades.

1. Installation and configuration of Yum

(1) Installation of Yum

Check if Yum is installed:

[Root@localhost ~]# Rpm-qa|grep Yum

If there is no display, the Yum tool is not yet installed on the system, the Yum installation package can be found on the CentOS system CD, and the following instructions are installed:

[Root@localhost ~]# RPM-IVH yum-*.noarch.rpm

Installation yum requires support from software packages such as Python-elementtree, Python-sqlite, Urlgrabber, and yumconf, which are available on the CentOS Linux system installation CD. If dependencies between packages occur during the installation of Yum, simply follow the dependency prompts to find the appropriate package installation until the Yum package is installed successfully.

The following is an example of an installation of an environment:

[Root@localhost ~]# RPM-IVH yum-2.4.3-1.c4.noarch.rpm

Warning:yum-2.4.3-1.c4.noarch.rpm:v3 DSA Signature:nokey, key ID 443e1821

error:failed dependencies:

Python-elementtree is needed by Yum-2.4.3-1.c4.noarch

Python-sqlite is needed by Yum-2.4.3-1.c4.noarch

Urlgrabber is needed by Yum-2.4.3-1.c4.noarch

Yumconf is needed by Yum-2.4.3-1.c4.noarch

[Root@localhost ~]# RPM-IVH python-elementtree-1.2.6-4.2.1.i386.rpm

Warning:python-elementtree-1.2.6-4.2.1.i386.rpm:v3 DSA Signature:nokey, key ID 443e1821

Preparing ... ########################################### [100%]

1:python-elementtree ########################################### [100%]

Root@localhost ~]# RPM-IVH sqlite-3.3.3-1.2.i386.rpm

Warning:sqlite-3.3.3-1.2.i386.rpm:v3 DSA Signature:nokey, key ID 443e1821

Preparing ... ########################################### [100%]

1:sqlite ########################################### [100%]

[Root@localhost ~]# RPM-IVH python-sqlite-1.1.7-1.2.i386.rpm

Warning:python-sqlite-1.1.7-1.2.i386.rpm:v3 DSA Signature:nokey, key ID 443e1821

Preparing ... ########################################### [100%]

1:python-sqlite ########################################### [100%]

[Root@localhost ~]# RPM-IVH python-urlgrabber-2.9.8-2.noarch.rpm

Warning:python-urlgrabber-2.9.8-2.noarch.rpm:v3 DSA Signature:nokey, key ID 443e1821

Preparing ... ########################################### [100%]

1:python-urlgrabber ########################################### [100%]

Root@localhost ~]# RPM-IVH centos-yumconf-4-4.5.noarch.rpm

Warning:centos-yumconf-4-4.5.noarch.rpm:v3 DSA Signature:nokey, key ID 443e1821

Preparing ... ########################################### [100%]

1:centos-yumconf ########################################### [100%]

[Root@localhost ~]# RPM-IVH yum-2.4.3-1.c4.noarch.rpm

Warning:yum-2.4.3-1.c4.noarch.rpm:v3 DSA Signature:nokey, key ID 443e1821

Preparing ... ########################################### [100%]

1:yum ########################################### [100%]