Shell Programming and Scripting

 
$ cat test.txt 
one two three
one two
one 
one two three
$ nawk '{if(NF<3){for(i=1;i<=3;i++){if($i!~/./){printf("NA ")}else{printf("%s ",$i)}if(i==3){printf("\n")}}}else{print}}' test.txt
one two three
NA NA NA 
one two NA 
NA NA NA 
one NA NA 
NA NA NA 
one two three

{
 i = 1
 if (NR == 1) {
  numfields=NF;
  for (i=1; i<=(numfields-1); i++) {
   printf "%s\t", $(i) ;
  }
  printf "%s\n", $(numfields) ;
 } else if (NR < 10) {
  for (i=1; i<=(numfields-1); i++) {
   printf "%s\t", $(i) ;
  }
  printf "%s\n", $(numfields) ;
 } 
}

$ a=$(awk 'NR==1{print NF}' infile)
$ awk -v val="$a" '{if(NF<val){for(i=1;i<=val;i++){if($i!~/./){printf("NA ")}else{printf("%s ",$i)}if(i==val){printf("\n")}}}else{print}}' infile
one two three
one two NA
one NA NA
one two three