`dd` command

Copy raw data between files and devices: disk images, bootable USBs, test files.

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Syntax

dd if=INPUT of=OUTPUT [bs=SIZE] [count=N] [status=progress]

Provided by the coreutils package. Run man dd for the full manual.

Option	What it does
`if=FILE`	Input file or device
`of=FILE`	Output file or device
`bs=SIZE`	Block size, e.g. 4M
`count=N`	Copy only N blocks
`status=progress`	Show progress
`conv=fsync`	Flush to disk before finishing

Write an ISO to a USB drive

sudo dd if=ubuntu.iso of=/dev/sdX bs=4M status=progress conv=fsync

Back up a disk to an image

sudo dd if=/dev/sda of=/backup/sda.img bs=4M status=progress

Restore an image

sudo dd if=/backup/sda.img of=/dev/sda bs=4M status=progress

Create a 1 GB test file

dd if=/dev/zero of=test.img bs=1M count=1024

Test write speed

dd if=/dev/zero of=./speedtest bs=1G count=1 oflag=dsync