gistfile1.pl

use strict;
use warnings;

use feature qw/ say /;

my $timeout  = 10; # seconds 
my $maxlines = 10;

eval {
    local $SIG{ ALRM } = sub {

        say "Reading...";
        my $counter = 0;
        while ( $counter < $maxlines ) {
            my $line = <>;
            print "$counter: $line";
            $counter++;
        }

        alarm $timeout;
    };

    say "Starting...";
    alarm $timeout;

    while ( 1 ) {}
};
if ( $@ ) {
        die "$@";
}