The regular expression to look for in the contents of the file. Uses Python regular expressions; see http://docs.python.org/2/library/re.html. Uses MULTILINE mode, which means ^ and $ match the beginning and end of the file, as well as the beginning and end respectively of each line of the file.
Does not use DOTALL, which means the . special character matches any character except newlines. A common mistake is to assume that a negated character set like [^#] will also not match newlines. In order to exclude newlines, they must be added to the set like [^#\n].
Note that, as of ansible 2, short form tasks should have any escape sequences backslash-escaped in order to prevent them being parsed as string literal escapes. See the examples.
repalce 默认使用python正则的multiline 模式，是支持匹配多行的
但是 .+ 这种无法匹配是因为 . 本身不匹配\n这类特殊字符
换用 [^#] 这中写法后，即可匹配多行
如果排除换行，要把\n加入用 [^#\n] 这中写法