$ cat gibberish
This is a couple
of lines of crud
$ cat gibberish | perl -Mstrict -Mwarnings -ne '
> my $x;
> BEGIN {$x = shift @ARGV; print qq{BEGIN - $x\n}}
> print qq{x = $x\n$_};' myarg
BEGIN - myarg
x = myarg
This is a couple
Use of uninitialized value in concatenation (.) or string at -e line 4, <> line 2.
x = 
of lines of crud
$