diff --git a/build.sh b/build.sh
index 6ec1cce..050fddb 100755
--- a/build.sh
+++ b/build.sh
@@ -5,8 +5,15 @@ set -e -x
 DIR=$(cd "$(dirname "$0")"; pwd -P)
 
 TOOLCHAIN_IMAGE="esp32-toolchain:latest"
-BUILD_DIR="$DIR/cmake-build"
+: ${BUILD_DIR:="$DIR/cmake-build"}
 DOCKERFILE="$DIR/Dockerfile"
+DOCKER_RUN_FLAGS=(--interactive --rm)
+
+# if stdin is a terminal, tell docker to allocate a tty
+if [ -t 0 ]; then
+    DOCKER_RUN_FLAGS+=(--tty)
+fi
+
 
 build_docker_container() {
     docker build -f "$DOCKERFILE" -t "$TOOLCHAIN_IMAGE" "$DIR"
@@ -16,7 +23,7 @@ build_docker() {
     build_docker_container
     docker run \
         --volume="$DIR:/esp/uas-ugv" \
-        --interactive --tty --rm \
+        "${DOCKER_RUN_FLAGS[@]}" \
         "$TOOLCHAIN_IMAGE" \
         /esp/uas-ugv/build.sh cmake "$@"
 }