Tool/Software for rotating atom coords around torsions?

Hey there comp-chemists!
Anyone know of a good free software in which you can specify one torsion angle around which to rotate a specified # of degrees, and save the cartesian coordinate outputs out to at least some 5 decimals?

I hear GaussView can do this (not free), and before, I used the software QMView which could, too, but is no longer supported for more modern Macs...
... otherwise I'll just suck it up and write my own script to do the math, but be thrilled if there's a fast/easy software to just download instead

Thanks for any insight!