yum clear

• 清理过期cache

yum clean expire-cache

Eliminate the local data saying when the metadata and mirrorlists were downloaded for each repo. This means yum will revali‐ .date the cache for each repo. next time it is used. However if the cache is still valid, nothing significant was deleted.

yum clean packages

Eliminate any cached packages from the system. Note that packages are not automatically deleted after they are downloaded.

yum clean headers

Eliminate all of the header files, which old versions of yum used for dependency resolution.

yum clean metadata

Eliminate all of the files which yum uses to determine the remote availability of packages. Using this option will force yum to download all the metadata the next time it is run.

yum clean dbcache

Eliminate the sqlite cache used for faster access to metadata. Using this option will force yum to download the sqlite metadata the next time it is run, or recreate the sqlite metadata if using an older repo.

yum clean rpmdb

Eliminate any cached data from the local rpmdb.

yum clean plugins

Tell any enabled plugins to eliminate their cached data.

yum clean all

Does all of the above.