]> newuidmap 1 User Commands shadow-utils &SHADOW_UTILS_VERSION; newuidmap set the uid mapping of a user namespace newuidmap pid uid loweruid count uid loweruid count ... The newuidmap sets /proc/[pid]/uid_map based on it's command line arguments and the uids allowed in /etc/subuid. There currently are no options to the newuidmap 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/subuid List of users subordinate user IDs. /proc/[pid]/uid_map Mapping of uids from one between user namespaces. login.defs5 , useradd8 , usermod8 , newusers8 , userdel8 , subuid5 .