Match any character including newline

A pattern with .* stops at the end of a line, and you want it to run across several.

import re

text = "BEGIN\nline one\nline two\nEND"
print(re.search(r"BEGIN.*END", text))
print(re.search(r"BEGIN.*END", text, re.DOTALL).group().count("\n"))
print(re.search(r"(?s)BEGIN.*END", text).group().count("\n"))
print(re.search(r"BEGIN[\s\S]*END", text).group().count("\n"))

None
3
3
3

Outside of the DOTALL mode a dot matches any character except the newline, which the re documentation states. The flag can be passed as an argument or switched on inside the pattern as (?s). The last form, a class of whitespace together with non-whitespace, is the portable one, since together they cover every character in any engine.

The name of the flag differs: JavaScript uses s, Perl s, and Ruby calls it m. grep works line by line, so it needs -z with -P to see a newline at all. A greedy .* with DOTALL swallows everything to the last END, so use .*? when you want the shortest span.