diff --git a/sh/build_demo_web.sh b/sh/build_demo_web.sh
index 97cad254..3d5f693c 100755
--- a/sh/build_demo_web.sh
+++ b/sh/build_demo_web.sh
@@ -37,7 +37,7 @@ done
 export RUSTFLAGS=--cfg=web_sys_unstable_apis
 
 # Clear output from old stuff:
-rm -f docs/${CRATE_NAME}_bg.wasm
+rm -f "docs/${CRATE_NAME}_bg.wasm"
 
 echo "Building rust…"
 BUILD=release
@@ -57,7 +57,7 @@ TARGET=`cargo metadata --format-version=1 | jq --raw-output .target_directory`
 echo "Generating JS bindings for wasm…"
 TARGET_NAME="${CRATE_NAME}.wasm"
 WASM_PATH="${TARGET}/wasm32-unknown-unknown/$BUILD/$TARGET_NAME"
-wasm-bindgen ${WASM_PATH} --out-dir docs --no-modules --no-typescript
+wasm-bindgen "${WASM_PATH}" --out-dir docs --no-modules --no-typescript
 
 # if this fails with "error: cannot import from modules (`env`) with `--no-modules`", you can use:
 # wasm2wat target/wasm32-unknown-unknown/release/egui_demo_app.wasm | rg env
@@ -66,15 +66,15 @@ wasm-bindgen ${WASM_PATH} --out-dir docs --no-modules --no-typescript
 # to get wasm-strip:  apt/brew/dnf install wabt
 # wasm-strip docs/${CRATE_NAME}_bg.wasm
 
-if [ "${FAST}" = false ]; then
+if [[ "${FAST}" = false ]]; then
   echo "Optimizing wasm…"
   # to get wasm-opt:  apt/brew/dnf install binaryen
-  wasm-opt docs/${CRATE_NAME}_bg.wasm -O2 --fast-math -o docs/${CRATE_NAME}_bg.wasm # add -g to get debug symbols
+  wasm-opt "docs/${CRATE_NAME}_bg.wasm" -O2 --fast-math -o "docs/${CRATE_NAME}_bg.wasm" # add -g to get debug symbols
 fi
 
 echo "Finished docs/${CRATE_NAME}_bg.wasm"
 
-if [ "${OPEN}" = true ]; then
+if [[ "${OPEN}" == true ]]; then
   if [[ "$OSTYPE" == "linux-gnu"* ]]; then
     # Linux, ex: Fedora
     xdg-open http://localhost:8888/index.html