#!/bin/sh

# Exit-Codes:
STATE_OK=0;STATE_WARNING=1;STATE_CRITICAL=2;STATE_UNKNOWN=3

usage()
{
 cat <<EOF
 usage: $0 interface
 This script checks interface state
EOF
}

if [ -z "$1" ]; then usage; exit $STATE_UNKNOWN; fi

int="$1"
res=$STATE_OK; txt="OK"

lnk=$(ip link show $int|head -n1 |sed 's/\(.*)(state \w*)(.*\)/\2/') #'

if [ "$lnk" != "state UP" ]; then res=$STATE_CRITICAL; txt="CRITICAL"; fi

echo "$txt:Interface $int $lnk"

exit $res