addgroup -g 1000 groupname
# -g GID Group id
# -S Create a system group
adduser -u 1000 -s /bin/sh -G groupname -D username
# -h DIR Home directory
# -g GECOS GECOS field
# -s SHELL Login shell
# -G GRP Group
# -S Create a system user
# -D Don't assign a password
# -H Don't create home directory
# -u UID User id
# -k SKEL Skeleton directory (/etc/skel)
# -g gid | groupname
groupadd -g 1000 humans
# Options:
# -f, --force exit successfully if the group already exists,
# and cancel -g if the GID is already used
# -g, --gid GID use GID for the new group
# -h, --help display this help message and exit
# -K, --key KEY=VALUE override /etc/login.defs defaults
# -o, --non-unique allow to create groups with duplicate
# (non-unique) GID
# -p, --password PASSWORD use this encrypted password for the new group
# -r, --system create a system account
# -R, --root CHROOT_DIR directory to chroot into
# -P, --prefix PREFIX_DIR directory prefix
# --extrausers Use the extra users database
# -u uid | -s shell | -G groups | username
useradd -u 1000 -s /bin/bash -G humans james
# Options:
# --badnames do not check for bad names
# -b, --base-dir BASE_DIR base directory for the home directory of the
# new account
# --btrfs-subvolume-home use BTRFS subvolume for home directory
# -c, --comment COMMENT GECOS field of the new account
# -d, --home-dir HOME_DIR home directory of the new account
# -D, --defaults print or change default useradd configuration
# -e, --expiredate EXPIRE_DATE expiration date of the new account
# -f, --inactive INACTIVE password inactivity period of the new account
# -g, --gid GROUP name or ID of the primary group of the new
# account
# -G, --groups GROUPS list of supplementary groups of the new
# account
# -h, --help display this help message and exit
# -k, --skel SKEL_DIR use this alternative skeleton directory
# -K, --key KEY=VALUE override /etc/login.defs defaults
# -l, --no-log-init do not add the user to the lastlog and
# faillog databases
# -m, --create-home create the user's home directory
# -M, --no-create-home do not create the user's home directory
# -N, --no-user-group do not create a group with the same name as
# the user
# -o, --non-unique allow to create users with duplicate
# (non-unique) UID
# -p, --password PASSWORD encrypted password of the new account
# -r, --system create a system account
# -R, --root CHROOT_DIR directory to chroot into
# -P, --prefix PREFIX_DIR prefix directory where are located the /etc/* files
# -s, --shell SHELL login shell of the new account
# -u, --uid UID user ID of the new account
# -U, --user-group create a group with the same name as the user
# -Z, --selinux-user SEUSER use a specific SEUSER for the SELinux user mapping
# --extrausers Use the extra users database