diff --git a/README.md b/README.md
index 8f98641..75691e1 100644
--- a/README.md
+++ b/README.md
@@ -1105,7 +1105,7 @@ basename() {
 
     tmp=${1%${1##*[!/]}}
     tmp=${tmp##*/}
-    tmp=${tmp%"${2/$1}"}
+    tmp=${tmp%"${2/$tmp}"}
 
     printf '%s\n' "${tmp:-/}"
 }
diff --git a/manuscript/chapter5.txt b/manuscript/chapter5.txt
index bbf7514..717369d 100644
--- a/manuscript/chapter5.txt
+++ b/manuscript/chapter5.txt
@@ -44,7 +44,7 @@ basename() {
 
     tmp=${1%${1##*[!/]}}
     tmp=${tmp##*/}
-    tmp=${tmp%"${2/$1}"}
+    tmp=${tmp%"${2/$tmp}"}
 
     printf '%s\n' "${tmp:-/}"
 }