How to check the progress of md5sum on many huge files?

I have some 500 files of 650MB each, named bigfile.000 to bigfile.199 and I need to calculate the MD5 checksum of all files combined. The command I am using is:

cat bigfile.* | md5sum

I have the time, and I understand it will take hours to complete, but I still want to check the progress. Is there any way to do so? Like piping something in between and do a word count that doesn't affect performance much?

Use pv. It is in the repos, and shows a nice progress bar.

pv bigfile.* | md5sum  

should do what you want.

Progress bar plus stats: ETA, ...:

pv -pteIrabT file | md5sum

For example:

# pv -pteIrabT hugefile.tar.lzo | sha1sum 
7.59GiB {----} 0:03:22 [39.1MiB/s] [38.5MiB/s] [>                          ]  7% ETA 0:41:47 ETA 19:45:26