Avoid filename conflicts and cleanup files after

docker/csharp/run.sh

@@ -1,6 +1,10 @@
 if [ "$EVAL_EXPR" = "true" ]; then
     csharp -e "$1"
 else
+    mkdir "$COUNT" && cd "$COUNT"
+
     echo "$1" > program.cs
     csc program.cs >/dev/null && mono program.exe
+
+    cd .. && rm -rf "$COUNT"
 fi