subcommand: Avoid referencing possibly undefined $ret.

[gsu.git] / common

diff --git a/common b/common
index cd07252fa1d6917905b41d868fcdbcb67d54f89b..e3268907a385cb5417ac60796f2f0a50fcbeed2f 100644 (file)
--- a/common
+++ b/common
@@ -1,5 +1,6 @@
 #!/bin/bash
-# (C) 2006-2011 Andre Noll
+# Copyright (C) 2006 Andre Noll
+# Licensed under the LGPL, version 3. See COPYING and COPYING.LESSER.
 
 _gsu_init_errors()
 {
@@ -38,7 +39,7 @@ EOF
 gsu_is_a_number()
 {
        result="$1"
-       if (("$1" == "$1")) &> /dev/null; then
+       if [ "$1" -eq "$1" ] &> /dev/null; then
                ret=$GSU_SUCCESS
        else
                ret=-$E_GSU_NOT_A_NUMBER