Bash tips, tricks and code snippets

Making a compressed disk image using dd and pv to indicate progress

See this reference.

Prerequisites

The program pv needs to be installed, if not:

sudo apt install pv

Process

Given the device point /media/sdc, the following creates image file SD_BACKUP.img.gz:

export BLOCKSIZE=`sudo blockdev --getsize64 /dev/sdc` && sudo dd if=/dev/sdc bs=1MB | pv -s $BLOCKSIZE | gzip -9 > SD_BACKUP.img.gz