My memory might be tricking me but I learnt about 'which' on a late '80s HP9000 running HP-UX, using bourne shell and it's output was the same as GNU which. But

My memory might be tricking me but I learnt about 'which' on a late '80s HP9000 running HP-UX, using bourne shell and it's output was the same as GNU which. But I might be swapping memories with early Linux.