Band:Black Sabbath
Album:Black Sabbath
Song:Black Sabbath

G
D
A
E   Standard tuning (they tune a half step down on the live Reunion, just so 
ya know)

Intro/Chorus (sometimes he slides up the fretboard at the end of the riff)
[——————————————————————]
[————5—————————————————]
[———————4—4—4—4—4—4—4—4]
[3—————————————————————]

Verse
[——————————————————————]
[——————————————————————]
[———————4—4—4—4—4—4—4—4]
[3———3—————————————————]

Just keep playing those two riffs. You'll know where they go. Then, after 
the last chorus, (when it changes) play this over and over
[———————]
[3h5—5—5]
[———————]
[———————]

Listen to see when this riff ends, and then play this until right before the 
end.
[——————————————————————————————————————————————]
[555555555555—3333333333—2222222222—11111111111]
[——————————————————————————————————————————————]
[——————————————————————————————————————————————]

At the end play this riff
[————————————————————————————————————————————————————————————————]
[55555555—3333333—5555555—3333333—5——5555——5553——3333——3335———5—5]
[————————————————————————————————————————————————————————————————]
[————————————————————————————————————————————————————————————————]

Just listen and you'll know where they go.