From abuse.ch one can get a plain text file with malware distributing URIs. I want to use this as a blacklist for squid proxy (not yet sure about runtime behavior). It should not be to hard to convert the URI file into a regex file for acl aclname url_regex ... using sed, but I struggle to find the squid regex syntax description to identify all special characters, that I have to escape.

  • the dquid page has a nice wiki, wiki.squid-cache.org/SquidFaq/SquidAcl
    – djdomi
    Mar 1, 2022 at 17:46
  • I know this wiki page, but it describes the acl syntax, not the regex syntax.
    – Thomas P
    Mar 2, 2022 at 7:06
  • You must be more specific and produce at least one example clearly stating what you intend to do. Anyway, assuming you just need to parse a hosts file https://urlhaus.abuse.ch/downloads/hostfile/, you may try this: search for ^(#.*$(\n|\r\n)?|127.*\t) and replace with ""
    – mjoao
    Jun 22, 2022 at 10:11
  • I'm looking for a description of the regex syntax itself. Which metacharacters, quantifiers, modifiers, ... are allowed, This differs slightly from perl to php to java to ...
    – Thomas P
    Jun 24, 2022 at 9:24

1 Answer 1


Squid understands GNUregex (Extended Regular Expressions, AKA: ERE REGEXP).
It does not fully understand Perl Regular Expressions, AKA: PCRE.
E.x: \w, \d, \W, \D, lookahead, negative lookahead, shy grouping, atomic groups, etc...)

Working examples:


NON WORKING examples but PCRE valid:

More info: https://www.gnu.org/software/gnulib/manual/html_node/Regular-expressions.html https://www.gnu.org/software/grep/manual/html_node/Regular-Expressions.html

  • While I think @mjoao is right, I would prefer him/her to add a link to the relevant SQUID configuration supporting such an answer.
    – EnzoR
    Sep 21 at 13:53

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