USERADD(8) (System Management Commands) (NAME) useradd - (SYNOPSIS) useradd [options] LOGIN useradd -D useradd -D [options] (DESCRIPTION) useradd . adduser(8) . -D useradd . useradd . ( -g -N -U USERGROUPS_ENAB ). (OPTIONS) useradd : --badname . -b, --base-dir BASE_DIR -d HOME_DIR . BASE_DIR . useradd HOME /etc/default/useradd /home . -c, --comment COMMENT . . -d, --home-dir HOME_DIR HOME_DIR . LOGIN BASE_DIR . HOME_DIR -M . -D, --defaults " " . -e, --expiredate EXPIRE_DATE . YYYY-MM-DD . useradd EXPIRE /etc/default/useradd ( ) . -f, --inactive INACTIVE . shadow . 0 . -1 shadow . shadow(5) . useradd INACTIVE /etc/default/useradd -1 . -F, --add-subids-for-system /etc/subuid /etc/subgid -r. -g, --gid GROUP . . . useradd USERGROUPS_ENAB /etc/login.defs . yes ( -U/--user-group ) . no ( -N/--no-user-group ) useradd GROUP /etc/default/useradd 100 . -G, --groups GROUP1[,GROUP2,...[,GROUPN]]] . . -g . . -h, --help . -k, --skel SKEL_DIR (skeleton) useradd . -m ( --create-home) . SKEL /etc/default/useradd /etc/skel . ACL (extended attributes) . -K, --key KEY=VALUE /etc/login.defs (UID_MIN UID_MAX UMASK PASS_MAX_DAYS ). : -K PASS_MAX_DAYS =-1 (aging) . -K : -K UID_MIN =100 -K UID_MAX=499 useradd -O . -l, --no-log-init lastlog faillog . lastlog faillog . useradd LOG_INIT /etc/default/useradd no lastlog faillog . -m, --create-home . ( -k ) . CREATE_HOME . SELinux . . -M, --no-create-home /etc/login.defs (CREATE_HOME) yes . -N, --no-user-group -g GROUP /etc/default/useradd . ( -g -N -U ) USERGROUPS_ENAB /etc/login.defs . -o, --non-unique UID . -u . UID . -p, --password PASSWORD . PASSWORD crypt(3) . . /etc/shadow. . : ( ) . . -r, --system . /etc/shadow SYS_UID_MIN-SYS_UID_MAX /etc/login.defs UID_MIN-UID_MAX ( GID ). useradd /etc/login.defs (CREATE_HOME) . -m . /etc/subuid /etc/subgid . -F . -R, --root CHROOT_DIR CHROOT_DIR CHROOT_DIR. . -P, --prefix PREFIX_DIR PREFIX_DIR . chroot (cross-compilation) . : / NIS LDAP . PAM . SELINUX . -s, --shell SHELL . SHELL /etc/default/useradd /etc/passwd . -u, --uid UID (ID). -o . . UID_MIN . -r UID_MAX . -U, --user-group . ( -g -N -U ) USERGROUPS_ENAB /etc/login.defs . -Z, --selinux-user SEUSER SELinux . SELinux . shadow selinux-user semanage(8) . (Changing the default values) -D useradd . -D useradd . : -b, --base-dir BASE_DIR . -d BASE_DIR . HOME /etc/default/useradd . -e, --expiredate EXPIRE_DATE . EXPIRE /etc/default/useradd . -f, --inactive INACTIVE . shadow(5) . INACTIVE /etc/default/useradd . -g, --gid GROUP (GID) . GID . GROUP /etc/default/useradd . -s, --shell SHELL . SHELL /etc/default/useradd . (NOTES) /etc/skel/ ( /etc/default/useradd ) . (CAVEATS) NIS LDAP . . NIS LDAP useradd . . . . . .. . . ls . ('-') ('+') ('~') (':') (',') (: ' ' : '\n' : '\t' ) . ('/') . . (CONFIGURATION) /etc/login.defs : CREATE_HOME (boolean) . . GID_MAX (number), GID_MIN (number) (GID) useradd groupadd newusers. GID_MIN ( GID_MAX) 1000 ( 60000) . HOME_MODE (number) (mode) . UMASK . useradd newusers . LASTLOG_UID_MAX (number) (UID) lastlog . (sparse) lastlog . LASTLOG_UID_MAX lastlog . MAIL_DIR (string) (mail spool). . . CREATE_MAIL_SPOOL /etc/default/useradd . MAIL_FILE (string) . MAIL_DIR MAIL_FILE useradd usermod userdel . MAX_MEMBERS_PER_GROUP (number) . ( ) /etc/group ( GID). 0 . ( ) . NIS 1024 . 25 . : ( Shadow). . PASS_MAX_DAYS (number) . . -1 ( ). PASS_MIN_DAYS (number) . . 0 ( ). PASS_WARN_AGE (number) . . . SUB_GID_MIN (number), SUB_GID_MAX (number), SUB_GID_COUNT (number) /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_UID_MIN (number), SUB_UID_MAX (number), SUB_UID_COUNT (number) /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 . SYS_GID_MAX (number), SYS_GID_MIN (number) useradd groupadd newusers. SYS_GID_MIN ( SYS_GID_MAX) 101 ( GID_MIN-1) . SYS_UID_MAX (number), SYS_UID_MIN (number) useradd newusers. SYS_UID_MIN ( SYS_UID_MAX) 101 ( UID_MIN-1) . UID_MAX (number), UID_MIN (number) useradd newusers. UID_MIN ( UID_MAX) 1000 ( 60000) . UMASK (number) . 022 . useradd newusers HOME_MODE . pam_umask umask . USERGROUPS_ENAB (boolean) yes userdel useradd . (FILES) /etc/passwd . /etc/shadow . /etc/group . /etc/gshadow . /etc/default/useradd . /etc/shadow-maint/useradd-pre.d/*, /etc/shadow-maint/useradd-post.d/* run-part . ACTION useradd SUBJECT username . useradd-pre.d . useradd-post.d . . /etc/skel/ . /etc/subgid (subordinate group IDs) . /etc/subuid (subordinate user IDs) . /etc/login.defs Shadow. (EXIT VALUES) useradd : 0 1 2 3 4 UID ( -o) 6 9 10 12 14 SELinux (AUTHOR) Julianne Frances Haugh. (REPORTING BUGS) shadow-utils : (COPYRIGHT) (C) 1991 - 1994 Julianne Frances Haugh. (C) 1996 - 2000 Marek Michalkiewicz. (C) 2000 - 2006 Tomasz Kloczko. (C) 2007 - 2025 Nicolas Francois. (SEE ALSO) chfn(1), chsh(1), passwd(1), crypt(3), groupadd(8), groupdel(8), groupmod(8), login.defs(5), newusers(8), subgid(5), subuid(5), userdel(8), usermod(8). shadow-utils 4.13 12/14/2025 USERADD(8)