This one won't be obvious until you find the hidden clue and follow its instructions.

Running the program reveals the clue. 

sub sub {$"='
jJPPJPJJjppHjpHAjpHAjpHAjpHAjPhAjpHAjpHAjpHAjpHAjpHAjpHAjpHAjpHAjpHAjp
HAjphajphajPhAjPhajPhaJPhAjphaJPHAJPHAJPHAJPhAJPhaJPHaJphajPhaJphaJPhA
jpHAJPHAJPHaJphajpHAjPhAjpHaJpHaJphaJphajPhAJPHAJPHAjPhAJPHaJpHAJPHAJP
HAjphajpPhjJPpjPJJAHHJaAAjAPhhJPJjahaPaPpaapaaAHahjpjJahaJAPPJapaaJPJJ
aPpjaPpAaPAJapAjAPaAAPhpjpjJapHaapaaAhJhAhJHaPjAaPAHAPaAJPHJJpjjahjhap
jaahapApAaJPjjaJPPApjaaHjjAPPjjPJjahAHaPpAahajApPJjpjJapJajPJJJpJPjphP
AHjjApHjjpjpjpjjAHHjjjppjpjjAHHjApAAAHpjAHAjApAAApHpAHjHAppAApHHApHpjp
JJApjaapHpApAjjpjjApAAApAjAppAahAjjpjjAppAApHpjpjjApAHAHApAppAApHAjpHj
JPjjAhapaPPaaPHaJpjjAPhHAHjpjpJJApAAAPhaApJaApjhaHJhJPhPjPJjjPJjAaJJap
aaAHjPapApaPHHAhJPAphaJpJJahhjJJppjpJJAhhjaPjAjPJjAHJhApAaaPjaaHJPApjH
APPjJPjjjpPJAHjPaPaaaPaHApAAAHPJjpjjahjhapAaapJaAHjpaPjHAPPJJPJjaPpaaP
HpJPJjApAAaPHAAPJAaPjhaHjHjppAJPjjApaPAPhHAHJPJpjjAHaJAppJapaaJpJJApJh
AppJApjAahJPJPHPJpJJAhJHApAAAHaJJPJjAhhJjjppjPjjAHhJaaPhAJPpAPJAAaJJap
pjAAHAjpHpjpjjjpjjAjpAApHpjpjjAHApAppAApHAjpHjjpjjAHAjAHjpAHpAjpjjApHH
ahaaahAjjpjjApAjAppAApApApApaPAAahjpApAAApHpAHAjjpjjApjHApHHApHjApHHah
JPjpjJaHJhaPJHaPPJapAaapHAApaaAHJhjphPJPjjjpJJahHJJjpPJpJJJPphJPhajpha
JPHAjPhAJPHAjphajphajPhAjpHAJPhaJPHAjpHaJpHaJpHAjPhAJPHAJPHAjPhAjPhAJP
haJPhajphaJPhAJPhaJPHaJpHAjphajphajphaJPhAjPhAjpHaJPhAjphaJPHaJPhaJpha
JPHAjpHAJPHAjphajPhAjPhAjpHAJPHAJPHaJpHaJpHaJpHAjPhAJPHAJPpHjJPpahHpAH
hPppApAjJJJaJjJhAAJapaJJaaHAaaApaappPhPPPPjjaahJAJhAHJJpPPPJAPapHPJAPh
';$_=$"&&s+\n++g;{$"!~s((.))() or$O=$O<<2|index lc"jApH",lc$1;unless (
++$%%4){'~'ne($O=chr$O)?print$O:exit}redo}}$==& sub(liverpole.8/13/06)

[download]

Update:  modified clue to take advantage of Ray Smith's observations.

Update 2023-07-12:  modified to get rid of no longer supported $* variable

s''(q.S:$/9=(T1';s;(..)(..);$..=substr+crypt($1,$2),2,3;eg;print$..$/

In reply to Letters to the Editor Japh by liverpole

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