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How can I search for a multiline pattern in a file?

I needed to find all the files that contained a specific string pattern. The first solution that comes to mind is using find piped with xargs grep:

find . -iname '*.py' | xargs grep -e 'YOUR_PATTERN'

But if I need to find patterns that spans on more than one line, I'm stuck because vanilla grep can't find multiline patterns.

Solution

  • So I discovered pcregrep which stands for Perl Compatible Regular Expressions GREP.

    the -M option makes it possible to search for patterns that span line boundaries.

    For example, you need to find files where the '_name' variable is followed on the next line by the '_description' variable:

    find . -iname '*.py' | xargs pcregrep -M '_name.*\n.*_description'

    Tip: you need to include the line break character in your pattern. Depending on your platform, it could be '\n', \r', '\r\n', ...