Count with sort and uniq

Question: Find all unique IP address that appear in a certain log message, and count how many times they appear.


Answer:

grep "log message" logfile.log | awk '{ print $18 }' | sort | uniq -c

Example:

[cygwin] $ grep "Missing post body" mpi.log |awk '{print $18}' |sort |uniq -c |sort -rn
      6 82.1.184.81
      6 212.121.212.149
      4 62.49.164.229
      2 62.140.196.160
 [cygwin] $

Note: the "sort -rn" at the end sorts results by number of occurrence