diff --git a/reframe/utility/sanity.py b/reframe/utility/sanity.py
index d3a47f9af5..0f8ec8d82b 100644
--- a/reframe/utility/sanity.py
+++ b/reframe/utility/sanity.py
@@ -363,6 +363,10 @@ def assert_found(patt, filename, msg=None, encoding='utf-8'):
         Any standard Python `regular expression
         <https://docs.python.org/3/library/re.html#regular-expression-syntax>`_
         is accepted.
+        The `re.MULTILINE
+        <https://docs.python.org/3/library/re.html#re.MULTILINE>`_ flag
+        is set for the pattern search.
+
     :arg filename: The name of the file to examine.
         Any :class:`OSError` raised while processing the file will be
         propagated as a :class:`reframe.core.exceptions.SanityError`.
@@ -503,6 +507,9 @@ def findall(patt, filename, encoding='utf-8'):
         Any standard Python `regular expression
         <https://docs.python.org/3/library/re.html#regular-expression-syntax>`_
         is accepted.
+        The `re.MULTILINE
+        <https://docs.python.org/3/library/re.html#re.MULTILINE>`_ flag
+        is set for the pattern search.
     :arg filename: The name of the file to examine.
     :arg encoding: The name of the encoding used to decode the file.
     :returns: A list of raw `regex match objects
@@ -556,6 +563,9 @@ def extractall(patt, filename, tag=0, conv=None, encoding='utf-8'):
         Any standard Python `regular expression
         <https://docs.python.org/3/library/re.html#regular-expression-syntax>`_
         is accepted.
+        The `re.MULTILINE
+        <https://docs.python.org/3/library/re.html#re.MULTILINE>`_ flag
+        is set for the pattern search.
     :arg filename: The name of the file to examine.
     :arg encoding: The name of the encoding used to decode the file.
     :arg tag: The regex capturing group to be extracted.
@@ -589,7 +599,6 @@ def extractsingle(patt, filename, tag=0, conv=None, item=0, encoding='utf-8'):
     :arg item: the specific element to extract.
     :returns: The extracted value.
     :raises reframe.core.exceptions.SanityError: In case of errors.
-
     '''
     try:
         # Explicitly evaluate the expression here, so as to force any exception