counting duplicates in a sorted sequence using command line tools

Question

I have a command (cmd1) that greps through a log file to filter out a set of numbers. The numbers are in random order, so I use sort -gr to get a reverse sorted list of numbers. There may be duplicates within this sorted list. I need to find the count for each unique number in that list.

For e.g. if the output of cmd1 is:

100  100  100  99  99  26  25  24  24 

I need another command that I can pipe the above output to, so that, I get:

100     3 99      2 26      1 25      1 24      2 

Answer 1

how about;

$ echo "100 100 100 99 99 26 25 24 24" \     | tr " " "\n" \     | sort \     | uniq -c \     | sort -k2nr \     | awk '{printf("%s\t%s\n",$2,$1)}END{print}' 

The result is :

100 3 99  2 26  1 25  1 24  2 

Answer 2

uniq -c works for GNU uniq 8.23 at least, and does exactly what you want (assuming sorted input).