I am Angelo. A systems engineer passionate about Linux and all open-source software. Although here I'm just another member of the family.

How to fix “dd unrecognised operand error” when trying to create a bootable USB

One of the useful commands in disk management is the dd command. This command also allows you to quickly and easily make bootable drives with a simple command. However, it can give error at some point of using it. Here’s how to fix dd unrecognised operand error when trying to create a bootable USB drive.


The DD command on Linux, which stands for Data Duplicator, is a low-level tool that allows you to back up, clone disks and even create bootable disks.

This command is included in all current Linux distributions and is the basis of many configuration scripts where you work with disks.

It is incredibly fast and, although very flexible in a short time and with some practice, can be mastered without problems.

The case…

An attempt has been made to make a bootable disk using the following command

sudo dd if=/home/angelo/Downloads/debian.iso of=/dev/sdc bs=4M status=progress && sync 

The command itself is quite explicit. Since it is making a bootable disk from the source in /dev/debian.iso to the /dev/sdc device using 4M blocks, the command is quite explicit.

However, running the above command gives this output on the screen

dd: unrecognized operand ' of=/dev/sdc'
dd unrecongnized operand error
dd unrecognised operand error

The reason for this error is that the \ character after where the input file is specified is missing. Therefore, remove it and the command will work

sudo dd if=/home/angelo/Downloads/debian.iso of=/dev/sdc bs=4M status=progress && sync 

And this will start the process.

Final thoughts

The dd command is simple to use, but bad syntax will have consequences. So, when you get an error like dd: unrecognized operand check the syntax and the trailing characters. That is the trick.

I hope this post will help you at some point.


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