a simple one liner is 
perl -ne 'if (/^<item>/){s/[ \t]+/ /g;print;}' test.txt

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I don't use \s because that would remove the newline character at the end of the line too.

Edit: made it a little shorter and added /g (which is of course the most important thing).

In reply to Re: formatting text by waldner
in thread formatting text by texuser74

Title:
Use:  <p> text here (a paragraph) </p>
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