2 # Copyright (C) 2016 Ian Kelling
4 # Licensed under the Apache License, Version 2.0 (the "License");
5 # you may not use this file except in compliance with the License.
6 # You may obtain a copy of the License at
8 # http://www.apache.org/licenses/LICENSE-2.0
10 # Unless required by applicable law or agreed to in writing, software
11 # distributed under the License is distributed on an "AS IS" BASIS,
12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 # See the License for the specific language governing permissions and
14 # limitations under the License.
17 trap 'echo "$0:$LINENO:error: \"$BASH_COMMAND\" returned $?" >&2' ERR
23 Get a host's mac address
25 If it's not in ip a, then ping it and look in the arp cache.
32 ip
=$
(host $host |
sed -rn 's/^\S+ has address //p')
34 # first sed joins ip a paragraphs into a single line.
35 if ip a |
sed -r '1{x;d};/^[0-9]/{: p;x;s/\n//g;b};$b p;H;d' \
36 |
sed -rn "/${ip//./\\.}/{s#^.*link/ether\s(\S+)\s.*#\1#p;q1}"; then
37 ping -c1 $ip &>/dev
/null
38 arp
-n $ip |
tail -n+2 |
awk '{print $3}'