$0 should not be trusted.

But if it's just about being short, I'll try too:

open F,$0;open O,">$$.pl";print O while <F>
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Or, cheating and even less secure:

open O,">$$.pl";print O `cat $0`
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Cheating even more:

`cp $0 $$.pl`
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The same, but secure (if cp can be trusted):

exec'cp',$0,"$$.pl"
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2;0 juerd@ouranos:~$ perl -e'undef christmas'
Segmentation fault
2;139 juerd@ouranos:~$
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