$  perl -e 'my $c = "foobar.txt"; open my $FH, "<", $c or die "cannot open $c $!"; '
cannot open foobar.txt No such file or directory at -e line 1.

$  perl -e 'my $c = "foobar.txt"; open my $FH, "<", $c or die "cannot open $c $!\n"; '
cannot open foobar.txt No such file or directory