diff --git a/day2/vhdl/run.sh b/day2/vhdl/run.sh
index 2094a93..4d5d87d 100755
--- a/day2/vhdl/run.sh
+++ b/day2/vhdl/run.sh
@@ -1,11 +1,13 @@
-#!/usr/bin/env sh
+#!/usr/bin/bash
 
 set -eu
 
-INPUT=$1
+INPUT=$(readlink --canonicalize-existing "$1")
 MODE=${2:-}
 GHDLFLAGS="--std=08 --workdir=workdir"
 
+cd "$(dirname "${BASH_SOURCE[0]}")"
+
 mkdir -p workdir
 
 if [[ $MODE = "--synth" ]]; then