Fix bashism/non-POSIX usage of $UID.

[grml-network.git] / sbin / grml-vnet

diff --git a/sbin/grml-vnet b/sbin/grml-vnet
index ccf62e9..7fa0d95 100755 (executable)
--- a/sbin/grml-vnet
+++ b/sbin/grml-vnet
@@ -1,6 +1,6 @@
 #!/bin/bash
-# Filename:      grml-addtun
-# Purpose:       Program to create tun/tap devices and add them to a bridge
+# Filename:      grml-vnet
+# Purpose:       program to create tun/tap devices and add them to a bridge
 # Authors:       Michael Gebetsroither <gebi@grml.org>
 # Bug-Reports:   see http://grml.org/bugs/
 # License:       This file is licensed under the GPL v2.
@@ -16,6 +16,9 @@ OPT_GROUP_=''
 OPT_BRIDGE_=''
 OPT_AUTO_='false'
 
+if [ $(id -ru) -ne 0 ] ; then
+  echo 1>&2 "Error: please run this script with uid 0 (root)." ; exit 1
+fi
 
 function printUsage()
 {
@@ -93,6 +96,12 @@ while getopts "du:g:b:ah" opt; do
 done
 shift $(($OPTIND - 1))
 
+if [[ $# < 1 ]]; then
+    echo "Error: Please give at least one device" >&2
+    printUsage
+    exit 1
+fi
+
 if [[ $OPT_DEL_ == 'false' ]]; then
     if [[ $OPT_BRIDGE_ != '' && $OPT_AUTO_ == 'true' ]]; then
         brctl showmacs "$OPT_BRIDGE_" &>/dev/null || brctl addbr "$OPT_BRIDGE_"