This article will provide the step to step instructions to create a bootable USB flash drive of CentOS 7 Minimal ISO on Windows, Mac, or Linux. The CentOS instance that we will install onto the bootable USB flash drive is CentOS-7-x86_64-Minimal-1503-01.iso.

 

Requirements

Windows: You will need to use a program like Cygwin. I have another blog post, teaching how to install Cygwin on Windows machines.

Macs and Linux: Your terminal will have the command already as a part of the machine.

 

Steps

I will show the steps being done on a Windows 10 machine with Cygwin already installed on the computer. If you use a Mac or Linux, the terminal will be able to do the same commands. First, we will download CentOS-7-x86_64-Minimal-1503-01.iso. This method should work with any CentOS minimal instance version 6.5 and greater. I have downloaded the minimal ISO inside:

C:/Users/huyle/Desktop/ISOs

Open Cygwin as an Administrator and change directory into this folder.

cd C:/Users/huyle/Desktop/ISOs

First, let’s check what /dev/sd removable devices we have. Type ls /dev/sd, don’t press Enter yet, then press the Tab button twice.

ls /dev/sd (Don't press Enter. Press Tab twice to see all the removable drives that start with /dev/sd)

You will see all the sd removable devices.

removable-sd-drives

Now, we will grab our USB Flash Drive. Plug your USB flash drive into your computer or laptop. Now, repeat the ls/dev/sd, then press Tab twice.

ls /dev/sd (Don't press Enter. Press Tab twice to see all the removable drives that start with /dev/sd)

removable-sd-drives-with-usb-flash-drive

 

You will see two new removable sd drives. Normally, the new sd drives will be: sdb and sdb1. Keep note of what appears after you plug your USB Flash Drive into the computer or laptop.

Since we are inside the folder where we kept our CentOS-7-x86_64-Minimal-1503-01.iso file. If we type:

ls

We should see the file inside the folder.

centos-is-in-folder

Now, we can add the CentOS-7-x86_64-Minimal-1503-01.iso on the USB Flash Drive with the dd command.

dd if=CentOS-7-x86_64-Minimal-1503-01.iso of=/dev/sdb bs=8M

dd-centos7

As long as the vertical line is blinking, then you can assume progress is being made. if is set to equal the ISO that you want to create the bootable USB flash drive. of selects the sd removable drive. In this case, we set of equal to /dev/sdb since it was the first /dev/sd that appeared that was new when we plugged our USB flash drive into the computer. bs selects the block size amount.

After a few minutes, the dd command should finish. You should be able to eject your USB flash drive, and boot a computer with the USB flash drive with the CentOS 7 Minimal ISO setup.

dd-command-finished

Safely eject your USB flash drive, and boot the computer on the USB Storage Device. CentOS 7 Minimal ISO setup will boot immediately afterwards.