For example, assuming CD-RW media that you want to erase first, and assuming your CD burner is known to the system as /dev/cdrw:
$ cdrecord -v -blank=fast -dev=/dev/cdrw filename.iso
Adjust as needed for your specifics. Run "man cdrecord" to learn about all the options.
To burn a DVD, check out the "growisofs" program. Standard cdrecord does not do DVD's.