Dans le man yum anglais je vois ceci :
man yum wrote: -C, --cacheonly
Tells yum to run entirely from system cache - does not download or update any headers unless it has to to perform the
requested action.
[root@host-192-168-1-2 ~]# yum -C update
Modules complémentaires chargés : langpacks
No packages marked for update
[root@host-192-168-1-2 ~]# yum update
Modules complémentaires chargés : langpacks
adobe-linux-x86_64 | 951 B 00:00:00
kde | 3.6 kB 00:00:00
rpmfusion-free-updates | 3.3 kB 00:00:00
rpmfusion-nonfree-updates | 3.3 kB 00:00:00
updates/20/x86_64/metalink | 26 kB 00:00:00
updates | 4.6 kB 00:00:00
virtualbox | 951 B 00:00:00
updates/20/x86_64/primary_db | 6.3 MB 00:00:20
(1/3): virtualbox/20/x86_64/primary | 3.5 kB 00:00:00
(2/3): updates/20/x86_64/pkgtags | 764 kB 00:00:03
(3/3): updates/20/x86_64/updateinfo | 517 kB 00:00:04
virtualbox 10/10