Linux下/etc/login.defs文件
/etc/login.defs文件定义了与/etc/password和/etc/shadow配套的用户限制设定。这个文件是需要的,缺失并不会影响系统的使用,但是也许会产生意想不到的错误。
如果/etc/shadow文件里有相同的选项,则以/etc/shadow里的设置为准,也就是说/etc/shadow的配置优先级高于/etc/login.defs。
# *REQUIRED* 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 #创建用户时,要在目录/var/spool/mail中创建一个用户mail文件
#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 #密码最大有效期
PASS_MIN_DAYS 0 #两次修改密码的最小间隔时间
PASS_MIN_LEN 5 #密码最小长度,对于root无效
PASS_WARN_AGE 7 #密码过期前多少天开始提示
# Min/max values for automatic uid selection in useradd
#创建用户时不指定UID的话自动UID的范围
UID_MIN 500 #用户ID的最小值
UID_MAX 60000 #用户ID的最大值
# Min/max values for automatic gid selection in groupadd
#自动组ID的范围
GID_MIN 500 #组ID的最小值
GID_MAX 60000 #组ID的最大值
# 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 #当删除用户的时候执行的脚本
#
# 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 #使用useradd的时候是够创建用户目录
# The permission mask is initialized to this value. If not specified,
# the permission mask will be initialized to 022.
UMASK 077 #创建后用户的权限掩码
# This enables userdel to remove user groups if no members exist.
#
USERGROUPS_ENAB yes #用MD5加密密码
。。。。。。