diff --git a/build.sh b/build.sh
index 75dd387..21c0325 100755
--- a/build.sh
+++ b/build.sh
@@ -3,30 +3,30 @@
 image="docker.io/antora/antora"
 cmd="--html-url-extension-style=indexify site.yml"
 
-if [ "$(uname)" == "Darwin" ]; then
+if uname | grep -iwq darwin; then
     # Running on macOS.
     # Let's assume that the user has the Docker CE installed
     # which doesn't require a root password.
     echo ""
     echo "This build script is using Docker container runtime to run the build in an isolated environment."
     echo ""
-    docker run --rm -it -v $(pwd):/antora $image $cmd
+    docker run --rm -it -v "$(pwd):/antora" "${image}" "${cmd}"
 
-elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
+elif uname | grep -iq linux; then
     # Running on Linux.
     # there isn't an antora/aarch64 container, antora can be installed locally
     # Check whether podman is available, else faill back to docker
     # which requires root.
 
     if [ -f /usr/local/bin/antora ]; then
-        /usr/local/bin/antora $cmd
-    elif [[ `uname -m` == "aarch64" ]]; then
+        /usr/local/bin/antora "${cmd}"
+    elif uname -m | grep -iwq aarch64; then
         echo "no antora/aarch64 container try just \`npm install -g @antora/cli @antora/site-generator-default\`"
     elif [ -f /usr/bin/podman ]; then
         echo ""
         echo "This build script is using Podman to run the build in an isolated environment."
         echo ""
-        podman run --rm -it -v $(pwd):/antora:z $image $cmd
+        podman run --rm -it -v "$(pwd):/antora:z" "${image}" "${cmd}"
 
     elif [ -f /usr/bin/docker ]; then
         echo ""
@@ -34,18 +34,19 @@ elif [ "$(expr substr $(uname -s) 1 5)" == "Linux" ]; then
         echo ""
 
         if groups | grep -wq "docker"; then
-	    docker run --rm -it -v $(pwd):/antora:z $image $cmd
-	else
+            docker run --rm -it -v "$(pwd):/antora:z" "${image}" "${cmd}"
+        else
+            echo "You might be asked for your password."
+            echo "You can avoid this by adding your user to the 'docker' group,"
+            echo "but be aware of the security implications."
+            echo "See https://docs.docker.com/install/linux/linux-postinstall/"
             echo ""
-            echo "This build script is using $runtime to run the build in an isolated environment. You might be asked for your password."
-            echo "You can avoid this by adding your user to the 'docker' group, but be aware of the security implications. See https://docs.docker.com/install/linux/linux-postinstall/."
-            echo ""
-            sudo docker run --rm -it -v $(pwd):/antora:z $image $cmd
-	fi
+            sudo docker run --rm -it -v "$(pwd):/antora:z" "${image}" "${cmd}"
+        fi
     else
         echo ""
-	echo "Error: Container runtime haven't been found on your system. Fix it by:"
-	echo "$ sudo dnf install podman"
-	exit 1
+        echo "Error: Container runtime haven't been found on your system. Fix it by:"
+        echo "$ sudo dnf install podman"
+        exit 1
     fi
 fi