Bulk User Provisioning from CSV

HR handed you a CSV of new hires to onboard: /root/case/users.csv, one account per line as login,uid,group (a leading comment line documents the columns). Provision every account: create each login with the exact UID from its row and add it to the group named in its row. That shared group already exists. This is the bread-and-butter of shell automation — parse the file and loop — but grading only cares about the result: read the live account databases and confirm every listed account exists with the right UID and group membership.