you get it on Route 36.
You use HM Rock Smash on smashable rocks.
rock smash go west of violet city and talk to the chubby guy
Bibarel he can learn waterfall, strenght, surf, rock smash, rock climb,
Once you Remove the Odd Tree (Sudowoodo) from the area near goldenrod, some fat guy will give you rock smash.
The fat boy/man wearing the pink top on route 36 (outside Violet city) gives it to you
Rock Smash isn't an HM in this game.
in Pokemon silver, gold, crystal, yellow, blue or red rock smash don't exist. in the new versions rock smash is a HM.
When you get to Violet city, you go to the top left corner of the town. Go through the tunnel area and go to the character in pink. She will give you the HM Rock Smash.
There is no Rock Smash HM in Pokémon Yellow.
there is no rock smash in Pokemon Red. there are only 5 HM's in Red version. the rock smash was introduced in the Silver and Gold versions.
You have to beat all 16 gym leaders to get rock climb I believe.
After obtaining all of the kanto and johto badges visit professer Oak and he will give you the HM rock climb.