message: creating an actual tempfile instead of using the same file
diff: # first export all current environment variables into a file.
  # We do that in order to keep the hierarchy of environment variables. Already defined ones are probably overwritten
  # via an `docker run -e VAR=VAL` system and they should still be used even they are defined in dotenv files.
  -export -p > /tmp/dotenv-exiting
  +TMPFILE=$(mktemp --tmpdir dotenv.XXXXXXXX)
  +export -p > $TMPFILE
  # set -a is short for `set -o allexport` which will export all variables in a file
  set -a
  @@ -32,4 +33,7 @@ set -a
  set +a
  # now export all previously existing environments variables so they are stronger than maybe existing ones in the dotenv files
  -. /tmp/dotenv-exiting
  \ No newline at end of file
  +. $TMPFILE
  +
  +# remove the tmpfile
  +rm $TMPFILE
  \ No newline at end of file
  