Shell history meme, huh?
history | awk '{a[$2]++ } END{for(i in a){print a[i] " " i}}' | sort -rn | head 7 15:37 7 11:38 5 18:54 5 15:36 5 15:33 5 15:27 4 19:26 4 17:26 3 9:25 3 16:58
I use tcsh. Good times.