Shell Programming and Scripting

VAR=12.12.12.12.

perl -i -ne's/(ip=.+)(ip=.+?,)/$1ip=$VAR,/;print' file

vif = [ 'ip=123.456.789.123,mac=00:16:3E:7D:16:BF,vifname=veth107', 'vifname=veth107a' ]

vif = [ 'ip=123.456.789.123,mac=00:16:3E:7D:16:BF,vifname=veth107', 'ip=xx.xx.xx.xx,vifname=veth107a' ]

#!/bin/bash

if [ $# -lt 2 ]; then
    echo
    echo "Usage - $(basename $0) FILE IP"
    echo "  FILE is input filename"
    echo "  IP is new IP address"
    echo
    exit 0
fi

sed "s/\(, 'ip=\)[^,]\+,/\1$2,/" $1

export VAR=12.12.12.12.

perl -i -ne's/(ip=.+)(ip=.+?,)/$1ip=$ENV{VAR},/;print' file

perl -i -ne's/(ip=.+vifname=.+)(vifname=.+)/$1ip=$ENV{VAR},$2/;print' file