I tried this but somehow $x seems to become undef after the first time through the implicit loop.

$ 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
$

[download]

I wonder what is causing this.

Cheers,

JohnGG

In reply to Re^2: Differentiating STDIN from arguments when using -n ? by johngg
in thread Differentiating STDIN from arguments when using -n ? by rduke15

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