diff --git a/SC2181.md b/SC2181-tell-inverting-return-value-will-overwrite-it.md
similarity index 96%
rename from SC2181.md
rename to SC2181-tell-inverting-return-value-will-overwrite-it.md
index f09c148..9191825 100644
--- a/SC2181.md
+++ b/SC2181-tell-inverting-return-value-will-overwrite-it.md
@@ -33,7 +33,7 @@ Apart from the redundancy, there are other reasons to avoid this pattern:
 
 To check that a command returns success, use `if mycommand; then ...`.
 
-To check that a command returns failure, use `if ! mycommand; then ...`.
+To check that a command returns failure, use `if ! mycommand; then ...`. Notice that `!` will overwrite `$?` value.
 
 To additionally capture output with command substitution: `if output=$(mycommand); then ...`