use warnings;
use strict;
open my $fh1, '<', '/thisfiledoesntexist'; warn $!;
open my $fh2, '<', '/etc/passwd'; warn $!;
my @lines = <$fh2>;
print "Read ",0+@lines," lines\n";

__END__

No such file or directory at - line 3.
Inappropriate ioctl for device at - line 4.
Read 45 lines