The manual page and help for the apt-cdrom linux command. Using apt-cdrom, CD-ROMs, USB flash drives, and other removable media can be added to APT as a package source. Apt-cdrom takes care of defining the disk structure, correcting any erroneous writes, and checking the index files. Adding CDs to the APT repository list is only possible using apt-cdrom and cannot be done manually. In addition, for a multi-disk package, each CD must be inserted and checked separately to allow the system to account for any write errors.