Reminds me of logtop: $ apt install logtop $ printf "%s\n" the foo the foo the defenestration the | logtop 7 elements 1 4 the 2

Reminds me of logtop: $ apt install logtop $ printf "%s\n" the foo the foo the defenestration the | logtop 7 elements 1 4 the 2 2 foo 3 1 defenestration It's implemented using an AVL tree (because it aimed to work on continuous streams like logs, so it's limited in size).