It sounds like you just want to modify the greediness of *: 

$content =~ s/(\w+)(: *)(.*?)\n<xxxxyyxxxx>\n/$1.":".$2.encode_base64(
+$3,'')."\n"/ges;

[download]
The ? following the * will cause it to be non-greedy and thus match at the earliest possible point in the string rather than the latest.

duff

In reply to Re^3: inline replacement in existing regex by duff
in thread inline replacement in existing regex by raiten

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