Multiple output files with dd utility: example

I just used this method to create a file MD5 "on the fly" meaning, one read operation when moving the file to a destination.

dd if=test.txt | tee >(md5 >> tmp/test.txt.md5) | dd of=tmp/test.txt or you can reverse the order of the destination and MD5
dd if=test.txt | tee >(dd of=tmp/test.txt) | md5 >> tmp/test.txt.md5

This worked for me.  The usage case would be when copying a file from "local" media to "remote" media (ex: local HDD to SAN volume)