-p is for pipe :) 
$ perl -le " warn 0+ -t STDIN ; warn 0+ -p STDIN "
1 at -e line 1.
0 at -e line 1.

$ echo | perl -le " warn 0+ -t STDIN ; warn 0+ -p STDIN "
0 at -e line 1.
1 at -e line 1.

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In reply to Re: Using PIped-in and invocation arguments in same script by Anonymous Monk
in thread Using PIped-in and invocation arguments in same script by justkar4u

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