my $file_name = ...;
my $kwd       = ...;

open my $fh, '<', $file_name
   or die("Unable to open file \"$file_name\": $!\n");

local $/ = "";
while (<$fh>) {
   chomp;
   my @fields = split /:/, $_;
   if ($fields[1] eq $kwd) {
      print "$_\n\n";
   }
}