Provided by: uidmap_18.104.22.168-1ubuntu9_amd64
newgidmap - set the gid mapping of a user namespace
newgidmap pid gid lowergid count [pid gid lowergid count [ ... ]]
The newgidmap sets /proc/[pid]/gid_map based on it's command line arguments and the gids allowed in /etc/subgid.
There currently are no options to the newgidmap command.
The only restriction placed on the login shell is that the command name must be listed in /etc/shells, unless the invoker is the superuser, and then any value may be added. An account with a restricted login shell may not change her login shell. For this reason, placing /bin/rsh in /etc/shells is discouraged since accidentally changing to a restricted shell would prevent the user from ever changing her login shell back to its original value.
/etc/subgid List of users subordinate user IDs. /proc/[pid]/gid_map Mapping of gids from one between user namespaces.