I have an Ubuntu 14.04 Live USB (32 GB).

  • Is it possible to create a bootable .iso file from the Live USB ?

how can I create a bootable ISO?

  • Is the second point actually how to clone an existing live USB? Do you need to cache the files as copies on disk first or is a direct copy to a new USB medium ok as well?
    – Byte Commander
    Oct 5, 2015 at 12:21
  • @ByteCommander clone?? you mean duplicate ..then No.And "cache the files as copies on disk first " ...yes =)
    – Ravan
    Oct 5, 2015 at 12:38

3 Answers 3


It should be enough to just cat the device. If your USB is, for example, /dev/sdb, you can do:

cat /dev/sdb > foo.img

to restore the image to a USB disk, do:

cat foo.img > /dev/sdb

Note that this approach will create an image file as large as the drive itself, even if the drive is almost empty. If the drive is not 100% full and you only want an iso of the used space, use genisoimage (install it with apt install genisoimage) instead:

genisoimage -o foo.iso /path/to/usb/mount/point
  • 1
    In case of 2 USB's 1 dd should be enough :D
    – Rinzwind
    Oct 5, 2015 at 11:51
  • @terdon thanks =)...my second one?...I will edit for clarity..
    – Ravan
    Oct 5, 2015 at 11:52
  • @Ravan see updated answer. I don't see why you would want to do that though. Just save the iso and keep that.
    – terdon
    Oct 5, 2015 at 12:04
  • 1
    What if the USB stick is much larger than the image needs, e.g. 8GB. Will the .iso file then be 8GB in size with much blank space in it or will it only eat up as much as necessary to hold the data? I'm referring to both the cat and the genisoimage methods.
    – Byte Commander
    Oct 5, 2015 at 12:20
  • 1
    @ByteCommander good point. The cat approach will indeed make a file as large as the device, irrespective of how much data you have. The geniso will make a file only as big as the used space of the device. Thanks, answer edited.
    – terdon
    Oct 5, 2015 at 12:37

I found a tool called Pinguy Builder which creates .iso from within the operating system.

Pinguy Builder will create an installable ISO of your current system.

You can burn this ISO to an USB drive or write it directly to a DVD.
The DVD/USB is bootable and so can then be booted from any PC.

Depending on what option you choose you can determine what type of ISO will be created.

If you pick “Dist”, it backups the whole system but excludes your home folder.

If you pick “Backup”, it backups the system and will include your home folder.

References :


How to launch Pinguy Builder on Ubuntu?


At this date, your tools for creating a bootable ISO in Linux include Systemback, Clonezilla, Distroshare, and possibly a few paid alternatives that I have not tried (e.g., TeraByte, PowerISO). I am still hoping to find a way to do it with dd.

There are many detailed tutorials for the ISO process in Systemback and Clonezilla. I have found Systemback much more user-friendly. It has been forked within the past year or two, and even the older version works for me on Ubuntu 21.04. But Clonezilla seems to be much more enduring and widely known. You may want to try a few different tools and see which works best for you, or at least view a few different tutorials.

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