Section: File Formats and Conversions (5)
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:
This file specifies the group IDs that ordinary users can use, with the newgidmap command, to configure gid mapping in a user namespace.
Tutoriais de Tecnologia Web