Shell Programming and Scripting

192.168.1.10
192.168.1.10
192.168.1.10
192.168.1.11
192.168.1.15
192.168.1.15
192.168.1.20
192.168.1.22

192.168.1.10 : 3
192.168.1.11 : 1
192.168.1.15 : 2
192.168.1.20 : 1
192.168.1.22 : 1

$ awk '{count[$1]++}END{for(j in count) print j":"count[j]}' file.txt

#!/bin/ksh93

typeset -A count

# create an associative array
while read ip
do
    (( count[$ip]++ ))
done < infile


# sort print the associative array
while (( 1 ))
do
   (( !${#count[@]} )) && break;
   k=(${!count[@]})
   for j in ${!count[@]}
   do
      (( ${count[$j]} > ${count[$k]} )) && k=$j
   done
   echo "$k : ${count[$k]}"
   unset count[$k]
done

192.168.1.10 : 3
192.168.1.15 : 2
192.168.1.20 : 1
192.168.1.11 : 1
192.168.1.22 : 1

for i in $(cat file.txt)
do
  echo "$i: $(grep -c $i file.txt)"
done | sort -u

 awk '{count[$1]++}END{for(j in count) print j":"count[j] |"sort -t: -k2r"}' urfile

for i in $(<file.txt)
do
  echo "$i: $(grep -c $i file.txt)"
done | sort -u -t. -k4