eject — Eject the removable media
Eject allows removable media (like CD-ROM, Floppy, Tape, JAZ, ZIP) to be ejected under software control. The command can also control some multi-disc CD-ROM changers, the auto-eject feature supported by some devices, and close the disc tray of some CD-ROM drives.
$ eject — Eject the default device, mostly CD.
$ eject -v — Same as above and show more info.
$ eject /dev/cdrom — Eject CD using device file name.
$ eject -t — Close the drive tray.
$ eject -vt — Same as above and show more info.
Read: man eject