diff --git a/helpers/size-sum.sh b/helpers/size-sum.sh
index 1fef087..59285a4 100755
--- a/helpers/size-sum.sh
+++ b/helpers/size-sum.sh
@@ -1,5 +1,7 @@
 #!/bin/bash
 # requires: coreutils
+[[ -f "$1" ]] || exit
 sz=$(cat $1)
-sz=$(($sz))
+sz=$((0$sz))
 echo "size-sum:" $(numfmt --to=iec $sz)
+[[ "$2" == "--rm" ]] && rm "$1"
\ No newline at end of file