open FILE,"interfacelink.txt" or die "cannot open file : $!";
#my $substring = "encap:";   #this is useful if search istring is long
while(<FILE>) {
 $line ="$_\n";
 $ind=$line=~ /up/;
 if ($ind){
 #print "$line\n";
  print "port is", $port, "=", substr($line,0,4)."\n";
 print "speed is", $speed, "=", substr($line,7,5)."\n";
 print "link is", $link, "=", substr($line,42,4)."\n";

 }
}