[dd] Show dd progress on the terminal

1. Experiment
dd a disk partition to file and execute at the background.
dd if=/dev/sdb1 of=/mnt/happy &

2. Check the pid of dd
pgrep -l '^dd$'

3. Show progress on terminal (two way)
A. Show one times
kill -SIGUSR1  8789

B. Every 2 min show once
watch -n 10 kill -SIGUSR1 8789

Reference :

• Show progress during dd copy