Shell Programming and Scripting

cat text.txt |
awk '{
  if ( count < 2 ){
    sub("CAR","REPLACE")
    count++
    }
  print
  }'

cat text.txt | awk '{if ( count < 3 ){ sub("CAR","REPLACE")} count++; print}'

awk '/CAR/ {
  if ( count++ < 2 )
    gsub("CAR","REPLACE")
  }1' file

 awk '/CAR/ && count < 2  {gsub("CAR","REPLACE");count++} {print $0;if(count == 2) {exit}}'  infile

REPLACE sweet head
hat red yellow
REPLACE book brown

CAR sweet CAR woman CAR
CAR red yellow
CAR book brown
tiger CAR cow CAR
CAR milk

awk '{while(index($0,"CAR") && ++n < 3){sub("CAR","REPLACE")}}1' file

 
$ awk 'BEGIN{RS="CAR";ORS="REPLACE"}NR>2{ORS="CAR"}1' file
REPLACE sweet REPLACE woman CAR
CAR red yellow
CAR book brown
tiger CAR cow CAR
CAR milk

awk '{
  if (cnt < 2)
    for (i=1;i<=NF;i++)
      if ($i=="CAR" && cnt<2)
        cnt += sub("CAR","REPLACE",$i)
   print
}' file