Updates IP addresses of a SmartOS VM (with less hassle)

vmip.sh

#!/usr/bin/bash

# Updates IP addresses of a SmartOS VM
#   This script stops the VM, updates the IP address(es),
#   and starts the VM back up.
#
# Usage:
#   vmip.sh <uuid> <ip1> [ip2] [ip3] [...]
#
# The IP's are applied to NICs of the VM in order. The
# first interface will be assigned <ip1>, the second
# interface will be assigned [ip2], etc. You can see 
# the order of the NICS by executing the following 
# command prior to running vmip:
#
#   vmadm get <uuid> | json nics

cmd="{\"update_nics\": ["

for (( i=2; i<= $#; i++ ))
do
idx=$(($i-2))
mac=$(vmadm get $1 |json nics |json $idx| json mac)

if [ $idx -gt 0 ]
then
cmd="$cmd, "
fi

cmd="$cmd { \"mac\":\"$mac\", \"ip\":\"${@:$i:1}\"}"
done

cmd="$cmd]}"
fi

cmd="$cmd { \"mac\":\"$mac\", \"ip\":\"${@:$i:1}\"}"
done

cmd="$cmd]}"

vmadm stop $1
echo $cmd | vmadm update $1
vmadm start $1 
vmadm get $1 | json nics

FWIW:

mac=$(vmadm get $1 |json nics |json $idx| json mac)

can be written as:

mac=$(vmadm get $1 |json nics.$idx.mac)

Are lines 36 through 39 meant to be duplicates of lines 30 through 33?