How to find patterns across multiple lines using grep?

Question

I want to find files that have \"abc\" AND \"efg\" in that order, and those two strings are on different lines in that file. Eg: a file with content:

blah bl         


        

Answer 1

Here is a solution inspired by this answer:

• if 'abc' and 'efg' can be on the same line:

    grep -zl 'abc.*efg' 
  

• if 'abc' and 'efg' must be on different lines:

    grep -Pzl '(?s)abc.*\n.*efg' 
  

Params:

• -P Use perl compatible regular expressions (PCRE).

• -z Treat the input as a set of lines, each terminated by a zero byte instead of a newline. i.e. grep treats the input as a one big line.

• -l list matching filenames only.

• (?s) activate PCRE_DOTALL, which means that '.' finds any character or newline.