Shell Programming and Scripting

one two three
one
two
three
four five six
four
five
six
seven eight nine
seven 
eight
nine
one two three

one two three
one
two 
four five six
four
five 
seven eight nine
seven 
eight 
one two three

$> awk 'NF==1 {if(a)print a; a=$0} NF==3 {print; a=""}' infile
one two three
one
two
four five six
four
five
seven eight nine
seven
eight
one two three

$> cat infile
one two three
one
two
three
four five six
four
five
six !!!
seven eight nine
seven !!!
eight
nine
one two three
$> awk 'NF<3 {if(a)print a; a=$0} NF==3 {print; a=""}' infile
one two three
one
two
four five six
four
five
seven eight nine
seven !!!
eight
one two three

#!/bin/bash

declare -a array
i=1
while read -r LINE
do
  set -- $LINE
  if [[ ${#} == 3 ]] ;then
     for((o=1;o<${#array[@]};o++))
     do
        echo "${array[$o]}"
     done
     echo "$LINE"
     i=1
  else
     array[$i]="$LINE"
     ((i++))
  fi
done <"file"