[edoceo]

I think shells did $ for vars first, then Perl added @ and % for arrays and hashes (and then $ was refs)

[efreak]

$string was in BASIC. I'm sure it's even older, though (the oldest BASIC I've used is GWBASIC).

[gmueckl]

I thought BASIC had $ at the end, not at the start? It has been a long time since those days, though.