diff --git a/Dockerfile b/Dockerfile
index 715fee0..280c4b3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -2,8 +2,8 @@ FROM ubuntu:22.04
 
 ENV DEBIAN_FRONTEND=noninteractive
 ARG USER
-ARG UID
-ARG GID
+ARG USER_ID
+ARG GROUP_ID
 
 # Force apt "--no-install-recommends" to limit the image size
 RUN echo 'APT::Install-Recommends   "0";'   >> /etc/apt/apt.conf.d/99local && \
@@ -79,7 +79,6 @@ ENV LC_ALL=en_US.UTF-8
 ENV LANG=en_US.UTF-8
 ENV LANGUAGE=en_US.UTF-8
 
-USER $USER
-
-WORKDIR /home/$USER
+USER "$USER"
 
+WORKDIR "/home/$USER"
diff --git a/create_user.sh b/create_user.sh
index 9adcdf0..a4938e8 100644
--- a/create_user.sh
+++ b/create_user.sh
@@ -1,14 +1,19 @@
 #!/bin/bash
 
+# If not provided, defaults to "ubuntu" with UID and GID of 1000
+USER=${USER:-"ubuntu"}
+USER_ID=${USER_ID:-1000}
+GROUP_ID=${GROUP_ID:-1000}
+
 # Create user
-groupadd -g $GID $USER
-useradd -m -s /bin/bash -u $UID -g $GID $USER
+groupadd -g "$GROUP_ID" "$USER"
+useradd -m -s /bin/bash -u "$USER_ID" -g "$GROUP_ID" "$USER"
 
 # Add the user to sudo group
 apt-get update
 apt-get -qq install sudo
-usermod -aG sudo $USER
+usermod -aG sudo "$USER"
 
 # Add user to sudoers without password
-echo "${USER} ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/$USER
-chmod 0440 /etc/sudoers.d/$USER
+echo "${USER} ALL=(root) NOPASSWD:ALL" > /etc/sudoers.d/"$USER"
+chmod 0440 /etc/sudoers.d/"$USER"