Each line in /etc/subgid contains a user name and a range of
       subordinate group ids that user is allowed to use. This is specified
       with three fields delimited by colons (":"). These fields are:

       o   login name

       o   numerical subordinate group ID

       o   numerical subordinate group ID count

       This file specifies the group IDs that ordinary users can use, with the
       newgidmap command, to configure gid mapping in a user namespace.

       Multiple ranges may be specified per user.

           Per user subordinate group IDs.

           Backup file for /etc/subgid.

       login.defs(5), newgidmap(1), newuidmap(1), newusers(8), subuid(5),
       useradd(8), userdel(8), usermod(8), user_namespaces(7).

shadow-utils 4.2                  03/26/2019                         SUBGID(5)
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