-p STDIN should tell you if STDIN is a pipe. The filetest operators are described in perlfunc.

---
print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';

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In reply to Re: detecting a pipeline on STDIN by pfaut
in thread detecting a pipeline on STDIN by Pardus

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