Trying to anonymize received headers for relayed messages from authenticated postfix users, there is an example from https://we.riseup.net/debian/anonymizing-postfix:
/^Received: from (.* \([-._[:alnum:]]+ \[[.[:digit:]]{7,15}\]\)).*?([[:space:]]+).*\(Authenticated sender: ([^)]+)\).*by (auk\.riseup\.net) \(([^)]+)\) with (E?SMTPS?A?) id ([A-F[:digit:]]+).*/ REPLACE Received: from [127.0.0.1] (localhost [127.0.0.1])$2(Authenticated sender: $3)${2}with $6 id $7
When editing the file regexp:/etc/postfix/header_checks the result is an error message:
line 15: repetition-operator operand invalid
Now my guess is that the above regex is in PCRE format, where my Postfix requests a POSIX compatible regular expression.
How to make the above regular expression POSIX regexp compliant for use in a Postfix header_checks file?
Your hunch is correct,
.*?is a PCRE construct:.*is normal “any character, as many times as possible, at least zero times”, and the trailing question mark changes that to “… as few times as possible …”. SUSv4 says:i haven’t studied the pattern too much, but you should be able to work around this particular incompatibility: the next subpattern is
([[:space:]]+), so you should be able to reformulate it as “any non-space character…”:or maybe just get rid of the problem by omitting the question mark. the space-eater is followed by another
.*after all.