Is there a basic linux command line, that does not make use of any 3rd party software, that places a bootable .iso file onto a USB memory stick that is then bootable and will install said linux?

I have the rhel-8.1 iso but it is 7.6gb.

I am out of dual-layer dvd's and would like to use my 32gb USB stick to install rhel-8.1.

Last time I tried which I think was CentOS-7.7 having put that onto USB via my windows10 pc, it booted but I then ran into some sata driver errors during install. And became really frustrated and just went back to dvd which worked.

Looking for a reliable, frustration-free, way to

  • plug 32gb usb stick into pc running centos 7.7
  • get the rhel-8.1 iso onto that usb stick and have that usb stick bootable
    • either by native command line
    • or using a free 3rd party software in linux, which i am ok with
  • boot a UEFI pc having that bootable usb stick and successfully install rhel 8.1 (or any linux iso) onto a single SSD connected via SATA.
  • 3
    The utility you're looking for is called cp: cp image.iso /dev/sdb where /dev/sdb is the name of the drive. Apr 28, 2020 at 16:13
  • @Arkadiusz Drabczyk Glad you found it! ron See unix.com/man-page/centos/1/cp and superuser.com/questions/620877/…
    – K7AAY
    Apr 28, 2020 at 16:42
  • 1
    so do not partition the usb key but just straight copy cp rhel-8.1-x86_64-dvd.iso /dev/sdb to the block device?
    – ron
    Apr 28, 2020 at 17:07
  • 2
    Yes, but be careful and you use the correct device. Apr 28, 2020 at 17:10
  • 1
    thanks, will try tonight.
    – ron
    Apr 28, 2020 at 17:17

2 Answers 2


There are many possibilities: cat, dd, pv, cp.

I think that cp is the easiest and should be available on each UNIX and Linux system. Use it like that:

cp <iso_image> /dev/<disk_name>

Use a disk name such as /dev/sdb, not a partition such as /dev/sdb1. Make a backup of data on the disk you're copying to because it will be replaced with contents of .iso image and be careful to use a correct disk name to not inadvertently overwrite your current filesystem. You shouldn't need to be root because on today's desktop Linux systems removable storage devices are owned by plugdev and users are already members of that that group.

  • that worked like a champ, thanks.
    – ron
    May 2, 2020 at 23:42
  • a given usb stick will no longer be usable and re-formattable under microsoft windows. To make it back to windows usable, in linux do parted /dev/sd? mklabel gpt; parted /dev/sd? mkpart primary 0% 100%; mkfs.fat /dev/sd? replacing ? with the correct letter of the block device your usb stick is. Then reformat in Windows with disk manager to make ntfs if desired.
    – ron
    May 2, 2020 at 23:45

You'd think dd would be a good choice. Sorry, but https://askubuntu.com/questions/25476/how-to-make-a-usb-drive-bootable-after-live-image-is-copied-into-it-using-dd-c says it's not reliable for this use.

Therefore, in the absence of anything better documented, would you consider using unetbootin which is designed to create a bootable Live USB drive?

Once installed, launch the app, and a menu appears. Select the Diskimage button and ISO should be chose in the spin box, then click on the triple dot box and browse to the location of your ISO file.

unetbootin menu

Make sure not to use persistence ("Space used to preserve...") on the next to last line of the menu screen.

  • 1
    It doesn't look like a command line utility to me. Apr 28, 2020 at 16:08
  • a simple one line command is preferred, but this is ok with me as long as it is free and it works.
    – ron
    Apr 28, 2020 at 17:18

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