diff --git a/Documentation/CodingGuidelines b/Documentation/CodingGuidelines
index 003393ed16..39ef53c237 100644
--- a/Documentation/CodingGuidelines
+++ b/Documentation/CodingGuidelines
@@ -188,6 +188,10 @@ For shell scripts specifically (not exhaustive):
    hopefully nobody starts using "local" before they are reimplemented
    in C ;-)
 
+ - Use octal escape sequences (e.g. "\302\242"), not hexadecimal (e.g.
+   "\xc2\xa2") in printf format strings, since hexadecimal escape
+   sequences are not portable.
+
 
 For C programs: