#!/bin/bash
s='"assets" : [ {
"downloadUrl" : "https://URL/repository/doc/v&/PROJECT/SUBP/csc-dbc1-repo01x-x11-20210301/DIR/DIR2",
"path" : "v&/PROJECT/SUBP/csc-dbc1-repo01x-x11-20210301/DIR/DIR2",'
grep -Eo -i 'csc-[a-z0-9]{4}-[a-z0-9]+-[a-z0-9]{3}-[0-9]{8}' <<< "$s"
IyEvYmluL2Jhc2gKcz0nImFzc2V0cyIgOiBbIHsKICAiZG93bmxvYWRVcmwiIDogImh0dHBzOi8vVVJML3JlcG9zaXRvcnkvZG9jL3YmL1BST0pFQ1QvU1VCUC9jc2MtZGJjMS1yZXBvMDF4LXgxMS0yMDIxMDMwMS9ESVIvRElSMiIsCiAgInBhdGgiIDogInYmL1BST0pFQ1QvU1VCUC9jc2MtZGJjMS1yZXBvMDF4LXgxMS0yMDIxMDMwMS9ESVIvRElSMiIsJwpncmVwIC1FbyAtaSAnY3NjLVthLXowLTldezR9LVthLXowLTldKy1bYS16MC05XXszfS1bMC05XXs4fScgPDw8ICIkcyI=