Soggy Bottom Boys: 
Man of Constant Sorrow
The song is in open F tuning - CFCFAF

here's the intro

------------------------------------
------------------------------------
--0-0-0-0-0-0-0--3b4h0---5-5-3--0---
--3h5-5-5-3h5-5--0-----3-----0--5---
--0---0-0-0---0--0-----0-----0--0---
------------------------------------

There are four chords used in the song: F, G#, A#, C

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--0----3----5---7--
--0----3----5---7--
--0----3----5---7--
--0----3----5---7--
-------------------

  F    G#   Bb   C

T he rhythm is somewhat hard.

(intro)
F Bb C F
                     C                            F
In constant sorro-ow, all thru his days.


F                                         Bb
I-I ...
                   C                  F
I've seen trouble, a...
F                                        Bb
I-I ....
                           C                          F
The place where I-I, was born ...
                            C                            F
The place where he-e, was born ...

Inst. F Bb C F

Repeats same chord progression throughout song.