through this media.
Plug your thumbdrive in and check for the device name through any of these commands. Typically the thumbdrive device name start with /dev/sdb, /dev/sdc, or the next sequence. For my case, the device name is /dev/sdc.
$ dmesg $ df -h $ mount
Write bootable ISO image to the USB thumbdrive using the dd command. Be patient as it takes a while to finish both commands.
$ sudo dd if=debian-7.4.0-amd64-CD-1.iso of=/dev/sdc bs=4M $ sync
Take the the USB drive and boot the machine using it. Before that, please remember to configure your BIOS to boot from removable media first. If you encounter this error message "isolinux.bin missing or corrupt" when booting from thumbdrive, then you've wrote the image to the thumbdrive incorrectly. Double check the dd command in step 2 again as the device name is /dev/sdc and not the partition name /dev/sdc1.
On a side note, I prefer Debian to Ubuntu installer as it is more verbose in explaining the reason of the installation procedure. The Ubuntu installer has been dumbed down or made easier for beginner user.