mjhjmtu

Debian's apt-get update fetches and updates the package index. Because I'm used to this way of doing things, I was surprised to find that yum update does all that and upgrades the system. This made me curious of how to update the package index without installing anything.

The check-update command will refresh the package index and check for available updates:

yum check-update

While yum check-update will check updates for installed packages, if it needs to be refreshed, so will most other commands.

The command that's strictly the equivalent of apt-get update is yum makecache ... however it's generally not recommended to run that directly, in yum.

Unfortunately yum check-update by default doesn't pull down changes from remote repositories until yum.conf's metadata_expire parameter has elapsed (default 90m).

So if you run yum check-update and get this:

$ sudo yum check-update
Loaded plugins: fastestmirror, security
Loading mirror speeds from cached hostfile

packagename version repo

This means that check-update is not performing an update, like apt-get update does.

You can see how long it will take before doing the "auto refresh" that all commands do underneath, by running this: yum repolist enabled -v

Work around:

use yum clean expire-cache (or yum clean all) first, then any future yum commands will auto-refresh the cache "when run." . Because future yum commands refresh the cache, this is in practice the same as apt-get update.

Or change the metadata_expire parameter of yum.conf to less than the default 90min, I guess.