USERNAME="${1:-test}"
-addgroup --gid 1013 ${USERNAME}
-adduser --system --uid=1013 --gid=1013 --home /home/${USERNAME} --shell /bin/bash ${USERNAME}
-adduser ${USERNAME} ${USERNAME}
+addgroup --gid 1013 "${USERNAME}"
+adduser --system --uid=1013 --gid=1013 --home "/home/${USERNAME}" --shell /bin/bash "${USERNAME}"
+adduser "${USERNAME}" "${USERNAME}"
-mkdir -p /home/${USERNAME}/.ssh
-cp /etc/skel/.[!.]* /home/${USERNAME}
+mkdir -p "/home/${USERNAME}/.ssh"
+cp /etc/skel/.[!.]* "/home/${USERNAME}"
-adduser ${USERNAME} sudo
-sed -i "\$ a ${USERNAME} ALL=\(ALL:ALL\) NOPASSWD: ALL" /etc/sudoers
+chown -R "${USERNAME}:${USERNAME}" "/home/${USERNAME}"
-chown -R ${USERNAME}:${USERNAME} /home/${USERNAME}
+if [ -f /etc/sudoers ]; then
+ adduser "${USERNAME}" sudo
+ sed -i "\$ a ${USERNAME} ALL=\(ALL:ALL\) NOPASSWD: ALL" /etc/sudoers
+fi