diff --git a/how-to-clean-uninstall-macos-apps-using-appcleaner-open-source-alternative/README.md b/how-to-clean-uninstall-macos-apps-using-appcleaner-open-source-alternative/README.md
index e476b9e..6a6beb1 100644
--- a/how-to-clean-uninstall-macos-apps-using-appcleaner-open-source-alternative/README.md
+++ b/how-to-clean-uninstall-macos-apps-using-appcleaner-open-source-alternative/README.md
@@ -18,7 +18,7 @@ Listed: true
 
 ```shell
 sudo mkdir -p /usr/local/bin
-sudo chown $USER:admin /usr/local/bin
+sudo chown ${USER}:admin /usr/local/bin
 ```
 
 ### Step 2: download [app-cleaner.sh](app-cleaner.sh) ([PGP signature](./app-cleaner.sh.sig), [PGP public key](https://sunknudsen.com/sunknudsen.asc))
diff --git a/how-to-spoof-mac-address-and-hostname-automatically-at-boot-on-macos/README.md b/how-to-spoof-mac-address-and-hostname-automatically-at-boot-on-macos/README.md
index fd945b6..ef8695c 100644
--- a/how-to-spoof-mac-address-and-hostname-automatically-at-boot-on-macos/README.md
+++ b/how-to-spoof-mac-address-and-hostname-automatically-at-boot-on-macos/README.md
@@ -25,7 +25,7 @@ Listed: true
 
 ```shell
 sudo mkdir -p /usr/local/sbin
-sudo chown $USER:admin /usr/local/sbin
+sudo chown ${USER}:admin /usr/local/sbin
 ```
 
 ### Step 2: source `/usr/local/sbin` folder