dd is a command-line utility for Unix and Unix-like operating systems whose primary purpose is to convert and copy files. -wiki

dd is very convenient but by default we cannot monitor the progress.

Here is the simple way to check dd progress.

Just open new terminal and command,

$ sudo kill -USR1 $(pgrep ^dd)

If you want regular update of dd progress,

$ watch -n30 'sudo kill -USR1 $(pgrep ^dd)'

By 30 seconds (-nSEC) it will update you dd progress automatically.