#!/bin/sh

#word frequency in textfile 
#usage:         ./wf -n < infile.txt
#default for n is 10

#this is a classic "programming pearl"


tr -cs A-Za-z\' '\n'     |
  tr A-Z a-z             |
    sort                 |
      uniq -c            |
        sort -k1,1nr -k2 |
          sed ${1:-$1}q