I found from mentioned URL as
To create a package, use the following command in your terminal:
curl -u <uid>:<pwd> -X POST http://localhost:7402/crx/packmgr/service/.json/etc/packages/mycontent.zip?cmd=create -d packageName=<name> -d groupName=<name>
But here in my case i need the current content from /content location and save in some other location. Just a content backup. Where we need to add this path in script.
Easy way is to create a package in crx with filter as /content and then use curl command to build it periodically and download them in file system using curl. Otherwise see  to how to create a package with filter in file system (Though it is not required)
We implemented Build using VURL command and working fine.
But when downloading package using command
curl -u uid:password http://localhost:4502/etc/packages/mypackages/test.zip
Getting error as "WEB_INF/vault/****
Please let me know how to overcome this issue
Its done .