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31 lines
1.3 KiB
31 lines
1.3 KiB
WareLogging, sort of. Regular expressions are wonderful (and wonderfully ugly) little creatures used to describe patterns in text. Useful in good TextEditors, or in a language like PerlLanguage. This page is a repository of useful regex stuff.
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= resources =
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* LinuxInANutshell, 2nd edition
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** p. 69, grep
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** p. 247, pattern matching
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** p. 208, perl quickref regex section
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= WareLogging =
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* PerlCompatibleRegularExpressions
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= thoughts & recipes =
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An EvolvingRegularExpression
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Use egrep for complex expressions. Otherwise you will have to escape ?, +, {, |, (, and ) in order to get them to behave as special characters. If you're used to writing in Perl or similar, keep in mind that vi / VimEditor pattern matching will treat at least some of these characters as literals unless you escape them.
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(?<! ''regex'') ''other stuff''
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is a zero-width negative lookbehind assertion. Matches, in
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other words, if ''regex'' does *not* precede the ''other stuff''.
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egrep -ri "^[a-z., ]+$" ./*.dir
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Shows lines which are just alphanumeric plus period,
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comma, and space characters in all files with
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the extension .dir.
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tail -f /var/log/p1k3.access_log | egrep -vi "(googlebot|slurp)"
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following log file, wanted to avoid bot traffic noise
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may well eat CPU.
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