NEWUSERS(8) (System Management Commands) (NAME) newusers - (SYNOPSIS) newusers [] [] (DESCRIPTION) newusers ( ) . ( passwd(5)) : pw_name:pw_passwd:pw_uid:pw_gid:pw_gecos:pw_dir:pw_shell pw_name . ( newusers ). . pw_passwd . pw_uid (UID) . () newusers . (UID) . ( newusers ) (UID) . (UID) . pw_gid (GID) . ( newusers ) (GID) . . GID GID . GID newusers GID . ( newusers ) GID newusers GID . pw_gecos GECOS . pw_dir . . newusers . newusers stderr . newusers . newusers . . pw_shell . . newusers . ( ) . ( ). PAM . . . (OPTIONS) newusers : --badname . -h, --help . -r, --system . (aging) /etc/shadow UID_MIN-UID_MAX SYS_UID_MIN-SYS_UID_MAX login.defs ( GID ). -R, --root CHROOT_DIR CHROOT_DIR CHROOT_DIR. . SELINUX . (CAVEATS) . (CONFIGURATION) /etc/login.defs : GID_MAX () GID_MIN () useradd groupadd newusers. GID_MIN ( GID_MAX) 1000 ( 60000) . HOME_MODE () (mode) . UMASK . useradd newusers . MAX_MEMBERS_PER_GROUP () . () /etc/group ( GID). 0 . ( split group) . NIS . 25 . : ( Shadow). . PASS_MAX_DAYS () . . 1- ( ). PASS_WARN_AGE () . 1- . . SUB_GID_MIN () SUB_GID_MAX () SUB_GID_COUNT () /etc/subuid useradd newusers ( ) SUB_GID_COUNT SUB_GID_MIN SUB_GID_MAX . SUB_GID_MIN SUB_GID_MAX SUB_GID_COUNT 100000 600100000 65536 . SUB_GID_DETERMINISTIC () yes useradd usermod newusers GID (deterministic) UID . : start = SUB_GID_MIN + ((UID - UID_MIN) * SUB_GID_COUNT) end = start + SUB_GID_COUNT - 1 UID GID ( LDAP NIS ) (UID) . SUB_GID_DETERMINISTIC usermod --add-subgids -S subgid . : UID_MIN UID_MIN . SUB_GID_COUNT SUB_GID_COUNT . UID_MIN SUB_GID_DETERMINISTIC . : () /etc/subgid (NFS ) . . SUB_GID_DETERMINISTIC no . (UID_MIN=1000 SUB_GID_MIN=100000 SUB_GID_COUNT=65536): +-----+--------------------+-----------------------------+ |UID | | GID | | | | | +-----+--------------------+-----------------------------+ |1000 | 100000 + | 100000-165535 | | | ((1000-1000) * | | | | 65536) | | +-----+--------------------+-----------------------------+ |1001 | 100000 + | 165536-231071 | | | ((1001-1000) * | | | | 65536) | | +-----+--------------------+-----------------------------+ |1002 | 100000 + | 231072-296607 | | | ((1002-1000) * | | | | 65536) | | +-----+--------------------+-----------------------------+ |1100 | 100000 + | 6653600-6719135 | | | ((1100-1000) * | | | | 65536) | | +-----+--------------------+-----------------------------+ : capacity = (SUB_GID_MAX - SUB_GID_MIN) / SUB_GID_COUNT : (600100000 - 100000) / 65536 ~~ 9155 . : SUB_GID_COUNT 4096 SUB_GID_MIN 100000 SUB_GID_MAX 10000000 : (10000000 - 100000) / 4096 ~~ 2417 . UNSAFE_SUB_GID_DETERMINISTIC_WRAP () : - ! SUB_GID_DETERMINISTIC yes . yes ( WRAP) UID (modulo arithmetic) (wrap around). (ring buffer) . : (container escape) . SUB_GID_MIN=100000 SUB_GID_MAX=200000 SUB_GID_COUNT=65536 A (UID 1000) [100000, 165535] B (UID 1001) A . B A . . no () SUB_GID_MAX (hard error) . . UNSAFE_SUB_GID_DETERMINISTIC_WRAP no . SUB_UID_MIN () SUB_UID_MAX () SUB_UID_COUNT () /etc/subuid useradd newusers ( ) SUB_UID_COUNT SUB_UID_MIN SUB_UID_MAX . SUB_UID_MIN SUB_UID_MAX SUB_UID_COUNT 100000 600100000 65536 . SUB_UID_DETERMINISTIC () yes useradd usermod newusers UID (deterministic) UID . : start = SUB_UID_MIN + ((UID - UID_MIN) * SUB_UID_COUNT) end = start + SUB_UID_COUNT - 1 UID UID ( LDAP NIS ) (UID) . SUB_UID_DETERMINISTIC usermod --add-subuids -S subuid . : UID_MIN UID_MIN . SUB_UID_COUNT SUB_UID_COUNT . UID_MIN SUB_UID_DETERMINISTIC . : () /etc/subuid (NFS ) . . SUB_UID_DETERMINISTIC no . (UID_MIN=1000 SUB_UID_MIN=100000 SUB_UID_COUNT=65536): +-----+--------------------+-----------------------------+ |UID | | UID | | | | | +-----+--------------------+-----------------------------+ |1000 | 100000 + | 100000-165535 | | | ((1000-1000) * | | | | 65536) | | +-----+--------------------+-----------------------------+ |1001 | 100000 + | 165536-231071 | | | ((1001-1000) * | | | | 65536) | | +-----+--------------------+-----------------------------+ |1002 | 100000 + | 231072-296607 | | | ((1002-1000) * | | | | 65536) | | +-----+--------------------+-----------------------------+ |1100 | 100000 + | 6653600-6719135 | | | ((1100-1000) * | | | | 65536) | | +-----+--------------------+-----------------------------+ : capacity = (SUB_UID_MAX - SUB_UID_MIN) / SUB_UID_COUNT : (600100000 - 100000) / 65536 ~~ 9155 . : SUB_UID_COUNT 4096 SUB_UID_MIN 100000 SUB_UID_MAX 10000000 : (10000000 - 100000) / 4096 ~~ 2417 . UNSAFE_SUB_UID_DETERMINISTIC_WRAP () : - ! SUB_UID_DETERMINISTIC yes . yes ( WRAP) UID (modulo arithmetic) (wrap around). (ring buffer) . : (container escape) . SUB_UID_MIN=100000 SUB_UID_MAX=200000 SUB_UID_COUNT=65536 A (UID 1000) [100000, 165535] B (UID 1001) A . B A . . no () SUB_UID_MAX (hard error) . . UNSAFE_SUB_UID_DETERMINISTIC_WRAP no . SYS_GID_MAX () SYS_GID_MIN () useradd groupadd newusers. SYS_GID_MIN ( SYS_GID_MAX) 101 ( GID_MIN-1) . SYS_UID_MAX () SYS_UID_MIN () useradd newusers. SYS_UID_MIN ( SYS_UID_MAX) 101 ( UID_MIN-1) . UID_MAX () UID_MIN () useradd newusers. UID_MIN ( UID_MAX) 1000 ( 60000) . UMASK () . 022 . useradd newusers HOME_MODE . pam_umask umask . (FILES) /etc/passwd . /etc/shadow . /etc/group . /etc/gshadow . /etc/login.defs Shadow. /etc/pam.d/newusers PAM newusers. /etc/subgid . /etc/subuid . (SEE ALSO) login.defs(5) passwd(1) subgid(5) subuid(5) useradd(8). shadow-utils 4.20.0 07/30/2026 NEWUSERS(8)