From 03ff31613137b7459880e62c0bc5a3785e7c27a9 Mon Sep 17 00:00:00 2001
From: encrypt <encrypt94@gmail.com>
Date: Wed, 25 Mar 2015 01:21:52 +0100
Subject: [PATCH] add checks on network device

---
 etherswitch.sh | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/etherswitch.sh b/etherswitch.sh
index 2b8e4f8..75c3dd7 100755
--- a/etherswitch.sh
+++ b/etherswitch.sh
@@ -4,6 +4,16 @@ STATE=0
 
 source ~/.etherswitch
 
+if [ -z "$interface" ]
+then
+    echo "interface is not set"
+    exit 1
+fi
+
+# check if $interface is a network device
+ip link show $interface > /dev/null
+if [ $? -eq 1 ]; then exit 1; fi   
+
 while :
 do
     ip link show $interface | grep -q "LOWER_UP"