diff --git a/tools/ngcp-api.inc b/tools/ngcp-api.inc
index 6f2d0e69b7..69291e9a8d 100644
--- a/tools/ngcp-api.inc
+++ b/tools/ngcp-api.inc
@@ -1,15 +1,23 @@
+#!/bin/bash
+
+set -e
+
 importcreds () {
-    if [ -f "$CREDS" ]; then
-        echo "$CREDS present, checking perms"
-        set +e; stat "$CREDS" | grep 'Access: (0600' 1>/dev/null; r=$?; set -e
-        if [ "$r" = "0" ]; then
-            echo "$CREDS permissions ok"
-            . "$CREDS"
-        else
-            echo "$CREDS must have permissions 600"
-            exit 1
-        fi
-    fi
-}
+  if [ ! -f "${CREDS}" ]; then
+    return
+  fi
 
+  if [ ! -r "${CREDS}" ]; then
+    echo "Error: cannot read ${CREDS}" >&2
+    exit 1
+  fi
 
+  echo "${CREDS} present, checking perms"
+  if stat "${CREDS}" | grep -q 'Access: (0600' 1>/dev/null ; then
+    echo "${CREDS} permissions ok"
+    . "${CREDS}"
+  else
+    echo "Error: ${CREDS} must have permissions 600" >&2
+    exit 1
+  fi
+}