Let's say you have a file that contains fruit.

apple
banana
orange
pineapple

This markup will print lines each line in the file until a line containing "orange" is matched.

my $file = "/path/to/file.txt";
open(FH, "<", $file) or die "cannot open $file $! \n";

while (my $line = <FH>) {
  print $line;
  last if $line =~ /orange/i; 
}

close FH;

Running this script will produce the following output.

apple
banana
orange