Thank you very much guys, and gals, SarahM's answer worked perfectly the first time through, and now maybe ill meet my deadlines :)

The pipe | char is a regex meta character and therefore needs to be escaped if you want to use it as a literal.

Substituing the following for the equivalent line of your script should solve the problem

       s/\Q$rem\E/$rep/go;
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When you want to replace all occurrences of a single character with a different single character, use tr/// instead of s///g. It is faster, and you won't ever be bitten by the meta-character problem, because tr/// does not respect meta-characters (no interpolation). Your documentative use of $rem and $rep would need to be replaced by a comment, of course.

# Translate all '|' (pipe) characters into ' ' (spaces).
while (<FILE>) {
  tr/|/ /;
  print OUTP;
}
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tr/// is in the perlop manpage. It does a lot more that just single/single transliteration, but this is where tr/// and s/// overlap in function.

FYI, you can do the equivalent under Windows with this one-liner:
perl -pe "tr/|/ /" filename > c:\joshperl\deptemp.txt

If it was *always* singles, i would do that, but occasionally i have to change sections. With this one, it is predominantly single-char. Thanks again people

The pipe character (|) means alternation inside a regex. It needs to be escaped. Try s/\Q$rem\E/$rep/g.

---
print map { my ($m)=1<<hex($_)&11?' ':'';
$m.=substr('AHJPacehklnorstu',hex($_),1) }
split //,'2fde0abe76c36c914586c';
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you need to escape the pipe, which sounds a lot more exciting than it is:

s/\|/ /go;
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will work. | is a control character in a regex, unless preceded by the escaping backslash.

update goodness. that's a new peak of redundancy. I was too busy wondering why s// /g does what it does. Can anyone explain?

tachyon yeah, it's the op's /o, and i forgot to take it out when i simplified the reply.

You do know that /o tells perl that any $scalar_var in the regex will never change its value so only compile the regex once don't you? If so why use it whan all you have is literals in your example?

cheers

tachyon

s&&rsenoyhcatreve&&&s&n.+t&"$'$`$\"$\&"&ee&&y&srve&&d&&print

s// /g replaces all null characters with a space. And it so happens that a null character is between every other character, so...

And by the way, s/|/ /g means replace either null or null with a space. :)

Does this answer your question?

Update: The 'null character' terminology isn't correct. See BrowerUK's note.

not really, but it restates it nicely enough. it's the so-happens part which intrigues me. why is there a null character there, and why only one?