I believe I have set HISTFILESIZE TO 2000 or something, I still need to compact it, and have commands like ls pruned by HISTIGNORE.

I use the awkscript below to compact it:

# histsort.awk --- compact a shell history file # Thanks to Byron Rakitzis for the general idea

     {
         if (data[$0]++ == 0)
             lines[++count] = $0
     }
     
     END {
         for (i = 1; i <= count; i++)
             print lines[i]
     }