in reply to How do I find out if STDIN or STDOUT are attached to a pipe?

The -p file test should work fine on stdin, viz: 
    $ sleep 1 | /usr/bin/perl -le 'print -p STDIN'
    1
    $ /usr/bin/perl -le 'print -p STDIN' < /dev/null

    $ /usr/bin/perl -v

    This is perl, version 5.005_03 built for sun4-solaris...

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The same thing happens with a 5.6 binary I have.

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