linux 基础知识之用户管理

useradd -D 可以呼出建立用户的默认值。

[root@localhost home]# useradd -D
GROUP=100 预设的群
HOME=/home 默认的家目录所在的目录
INACTIVE=-1 密码失效日
EXPIRE=         账号失效日
SHELL=/bin/bash 预设的shell
SKEL=/etc/skel 用户家目录的内容数据参考目录
CREATE_MAIL_SPOOL=yes 是否主动帮使用者建立邮箱

系统会默认建立用户的家目录是和 etc/login.defs 这个档案内的CREATE_HOME yes

[bobby@localhost ~]$ cat /etc/login.defs
# *REQUIRED*
#   Directory where mailboxes reside, _or_ name of file, relative to the
#   home directory.  If you _do_ define both, MAIL_DIR takes precedence.
#   QMAIL_DIR is for Qmail
#
#QMAIL_DIR      Maildir
MAIL_DIR        /var/spool/mail
#MAIL_FILE      .mail

# Password aging controls:
#
#       PASS_MAX_DAYS   Maximum number of days a password may be used.
#       PASS_MIN_DAYS   Minimum number of days allowed between password changes.
#       PASS_MIN_LEN    Minimum acceptable password length.
#       PASS_WARN_AGE   Number of days warning given before a password expires.
#
PASS_MAX_DAYS   99999
PASS_MIN_DAYS   0
PASS_MIN_LEN    5
PASS_WARN_AGE   7

#
# Min/max values for automatic uid selection in useradd
#
UID_MIN                   500
UID_MAX                 60000

#
# Min/max values for automatic gid selection in groupadd
#
GID_MIN                   500
GID_MAX                 60000

#
# If defined, this command is run when removing a user.
# It should remove any at/cron/print jobs etc. owned by
# the user to be removed (passed as the first argument).
#
#USERDEL_CMD    /usr/sbin/userdel_local

#
# If useradd should create home directories for users by default
# On RH systems, we do. This option is overridden with the -m flag on
# useradd command line.
#
CREATE_HOME     yes （在不加-M及-m时是否主动建立家目录）

# The permission mask is initialized to this value. If not specified,
# the permission mask will be initialized to 022.
UMASK           077

# This enables userdel to remove user groups if no members exist.
#
USERGROUPS_ENAB yes

# Use MD5 or DES to encrypt password? Red Hat use MD5 by default.
MD5_CRYPT_ENAB yes

[bobby@localhost ~]$

useradd -d /tmp/user user 创建用户后su - user 进去之后执行 pwd 显示出来的是这个

用户的家目录，和root家目录理解是不样的root进入家目录是cd ~