Improved mac support

src/errors/ExpectedCLIParameter.go

@@ -0,0 +1,13 @@
+package errors
+
+import "fmt"
+
+// ExpectedCLIParameter error is created when a command line parameter is missing.
+type ExpectedCLIParameter struct {
+	Parameter string
+}
+
+// Error generates the string representation.
+func (err *ExpectedCLIParameter) Error() string {
+	return fmt.Sprintf("Expected parameter '%s'", err.Parameter)
+}