yum exercise

yum (Yellow Dog updater Modified) is an answer to the difficulty of locating and reconciling interdependent rpm packages. rpm is a local solution, yum a global one superimposed on rpm in network environments.

Examine yum's configuration file:

cat  /etc/yum.conf

Change the value of "keepcache" from 0 to 1 with an editor. Note the cachedir setting, to learn where yum stores the rpm package files and related information it downloads and installs for you in the course of operation. Examine what's in there currently:

ls  -lR  /var/cache/yum  |  more

Find out which repositories yum is "pointing" to, by looking into /etc/yum.repos.d which contains effectively a repository list:

ls  /etc/yum.repos.d

one repository per file. "Teach" your system another, new repository for its use by placement of another, new repository file in /etc/yum.repos.d. As a model of what a repository file must contain, look at one.

more  /etc/yum.repos.d/fedora-core.repo

The central item is the URL that tells yum where it can find the indicated repository, with its treasure of collected rpm packages. To add a third-party repository (not maintained by the Fedora project), find one at www.fedoratracker.org. The site gives you the fully-formed text to be placed in a new repository file to make yum aware of that repository. Do so, naming the file something indicative of the repository's name. (ATrpms is a good one; name the new file atrpms.repo. In it, change "enabled" from 0 to 1 using an editor.) From among the repositories yum knows, find out for which packages updates are available:

yum  check-update

This checks for updates of all packages that are installed on your system (recorded by rpm and revealed by "rpm -qa"). If your installation is late in the version cycle and you have not updated it, there will be updates for just about every package. If you installed a version of Fedora yesterday that was released the day before, there may be none. Probably you have firefox installed on your system but not yumex. (Yumex is a graphical front-end to yum; firefox is a graphical http client.) Find out about getting their most up-top-date versions onto your system.

yum  install  yumex  firefox

If it offers to install and/or update either or both (expected), go ahead. After yumex has been installed and firefox updated, repeat the same command.

yum  install  yumex firefox

This time it should report that there's nothing to do. Because yum has just done it. Now that you have it, launch yumex.

yumex  &

Note yumex is just a graphical front-end to the character yum you've just been using. Re-examine the cache

ls  -lR  /var/cache/yum  |  more

You should see residual files there from having installed yumex and firefox, because you earlier set "keepcache" to 1 in yum.conf. Otherwise, yum would, after using a file it downloaded, clean up after itself by deleting it.