diff --git a/README.md b/README.md
index 6fbc687..5ce8461 100644
--- a/README.md
+++ b/README.md
@@ -151,6 +151,9 @@ do not have a defined ordering.
 When writing nested constructs, keep in mind that YAML is whitespace-sensitive.
 Following the formatting used in the examples is a good idea.
 
+Also, note that `~` in YAML is the same as `null` in JSON. If you want a single
+character string containing a tilde, make sure to enclose it in quotes: `'~'`
+
 ### Link
 
 Link commands specify how files and directories should be symbolically linked.