Linux dd Command Explained for Beginners (8 Examples)

The dd command in Linux is a powerful and versatile tool for copying and converting files and disk images. It is short for "data duplicator" and is commonly used for tasks like creating disk images, cloning drives, and transferring data between devices. In this article, we will explain the basics of the dd command and provide 8 examples to help beginners understand how to use it effectively.

1. Basic Syntax of dd Command

The basic syntax of the dd command is as follows:

dd [options] input_file output_file

Here, the input_file is the source file or device from which data will be read, and the output_file is the destination file or device where the data will be written. The options can be used to customize the behavior of the dd command, such as setting block sizes or skipping certain parts of the input file.

1. Copying a File

To copy a file using the dd command, you can specify the input_file as the source file and the output_file as the destination file. For example, to copy a file named "input.txt" to a new file named "output.txt", you can use the following command:

dd if=input.txt of=output.txt

1. Copying a Disk Image

You can also use the dd command to create a disk image by specifying a disk or partition as the input_file and a file as the output_file. For example, to create an image of /dev/sda and save it to a file named "disk_image.img", you can use the following command:

dd if=/dev/sda of=disk_image.img

1. Cloning a Drive

To clone a drive using the dd command, you can specify the input_file as the source drive and the output_file as the destination drive. For example, to clone /dev/sda to /dev/sdb, you can use the following command:

dd if=/dev/sda of=/dev/sdb

1. Copying Data with a Specific Block Size

You can use the bs option to specify a custom block size for reading and writing data with the dd command. For example, to copy data with a block size of 1MB, you can use the following command:

dd if=input.txt of=output.txt bs=1M

1. Displaying Progress

You can display the progress of the dd command by using the status=progress option. This will show the amount of data that has been processed and the transfer speed. For example, to display the progress of copying a file named "input.txt" to a new file named "output.txt", you can use the following command:

dd if=input.txt of=output.txt status=progress

1. Converting File Formats

You can use the conv option to specify conversion options for the dd command. For example, you can convert a file from uppercase to lowercase by using the command:

dd if=input.txt of=output.txt conv=ucase

1. Erasing Data

You can use the dd command to erase data from a drive by writing zeroes or random data to it. For example, to overwrite a drive with zeroes, you can use the following command:

dd if=/dev/zero of=/dev/sda

In conclusion, the dd command in Linux is a versatile tool for copying and converting files and disk images. By understanding the basics of its syntax and options, beginners can effectively use the dd command for a variety of tasks. The examples provided in this article are just a starting point, and there are many more advanced use cases for the dd command that you can explore as you gain experience with it.