If you already started the dd command and need to see the progress and if it's stuck or not, use this line:

watch -n5 'sudo kill -USR1 $(pgrep ^dd)'

This will result in DD showing the following output, instead of being there without any progress shown:

[root@mbpc-pc log]# nice -n +19 dd if=/dev/sdj of=/dev/sdi
815429980672 bytes (815 GB) copied, 69693.4 s, 11.7 MB/s
1592775457+0 records in
1592775457+0 records out
815501033984 bytes (816 GB) copied, 69698.6 s, 11.7 MB/s
1592904529+0 records in
1592904529+0 records out

If you have not yet started your dd command, use and install pv (yum install pv):

dd if=/dev/urandom | pv | dd of=/dev/null

Cheers,
TK