awk '
BEGIN {
pos='$1' 
lon='$2' 
lim='$3'+0
}
{
n=substr($0,pos,lon)+0
if( n <= lim )
  {    
   printf "\t%s\n", $0  
   net++
  }
}
END {
printf "\n\t Etoiles selectionnees: %3d\n\n", net
} '