Can anyone help me find blues song from episode of

ER on NBC 2/09/06? I don't know if anyone knows the song title or any information about the blues song that the homeless man sings while playing piano. If you do please post it so I can hear more. It was sounding really good. Hope someone knows. Thanks for your effort.
I know blues, I know nothing of ER. Can you hum a few bars?
"Many Rivers to Cross" Actually a Reggae song written (I think) by Jimmy Cliff; recorded on "Harder They Come."
Excellent version recorded by Linda Ronstadt in the '70s(?)
Happy Listening!
Thanks Joe. I will probably check out both versions in the near future. Thanks for your help. I really appreciate it.
Theirs a great Simply Vinyl reissue of The Harder They Come soundtrack for you vinyl lovers...Cheers,
the animals did a version in late 70's too