Macon has several recordings about Mules, and I guess if they're not posted here yet I'll add all of them on this thread.

Before I get into this song, it is known both as "Greenback" and "Whoa Mule," though Uncle Dave Macon never made more than one or two recordings of it. The "Greenback" version omits the word "nigger" and has an added first stanza which my recording (the "Whoa Mule" version, as Youtube calls it) does not.

GREENBACK (Whoa Mule)

Once I had a brand new overcoat and I hung it on the wall
A nigger stole that overcoat, and whoa, mule, whoa

CHORUS
Hi yo that greenback, greenback, hi yo today
Hi yo, that greenback, that nigger walked away

You may ride the old gray horse, I will ride the roan
You may court your own true love, and leave my wife alone

CHORUS

Used for to live in the mountain, now I live in town
Boardin' at a big hotel, sparkin' all around

CHORUS

There's also a verse in a book that I used to help verify my transcription that that my recording doesn't have which goes as follows:

"If I had a scoldin' wife, I tell you what I'd do
Run my finger down her throat, gag her with my thumb"

Lyrics transcribed from: https://www.youtube.com/watch?v=2QkCLr-VN70

Book source: Folk Songs of Middle Tennessee: The George Boswell Collection By Charles K. Wolf