$ perl -e"die __FILE__"
-e at -e line 1.

$ echo die __FILE__ > thefileis

$ perl -e"die __FILE__"
-e at -e line 1.

$ echo die __FILE__ > thefileis

$ perl thefileis
thefileis at thefileis line 1.

$ perl D:\thefileis
D:\thefileis at D:\thefileis line 1.

$