For modifying VMs

mod_vm.sh

#!/bin/bash

set -x

ls /etc/libvirt/qemu/ | grep ".xml" | sed s/.xml// > vm-names.txt


for name in $(cat vm-names.txt); do
	# dumping xml files
	virsh dumpxml $name > ${name}.xml

	# editing
	cat ${name}.xml | sed s/2097152/1097152/

	# importing xml files
	virsh define ${name}.xml

	virsh start $name

	rm ${name}.xml
done

rm vm-names.txt