Linux dd command

The dd command in Linux is a versatile utility used for copying and converting files or data streams. It is often referred to as “disk dump” because it can be used to create disk images or perform low-level operations on storage devices.

The basic syntax of the dd command is as follows:

dd [options] if=<input_file> of=<output_file>

Here’s how you can use the dd command:

1. Copying a file:
   To copy the contents of one file to another, you can use the if (input file) and of (output file) options. For example, to copy the contents of file1.txt to file2.txt, you would run:

   dd if=file1.txt of=file2.txt

2. Copying a storage device:
   The dd command can be used to create disk images or clone storage devices. You need to specify the input file as the storage device and the output file as the destination file or device. For example, to create a disk image of a USB drive named /dev/sdb and save it to backup.img, you would run:

   sudo dd if=/dev/sdb of=backup.img

Please note that when copying storage devices, it’s crucial to ensure you have the correct input and output devices specified to avoid data loss.

3. Setting block size:
   By default, dd uses a block size of 512 bytes. You can specify a different block size using the bs (block size) option. For example, to set the block size to 4 kilobytes (4K), you would include the bs option followed by the desired value:

   dd if=input_file of=output_file bs=4K

4. Monitoring progress:
   By default, dd does not provide progress information. However, you can use the status=progress option to display the progress and transfer statistics. For example:

   dd if=input_file of=output_file status=progress

These are just a few examples of how to use the dd command. The dd command provides numerous options, such as skipping input blocks, specifying input and output sizes, and performing conversions. It is a powerful command that requires caution, as incorrect usage can result in data loss. I recommend referring to the dd command’s manual page by running man dd in the terminal for more detailed information on the available options and their usage.