Linux 用户管理

一、用户添加、删除

1.1 useradd

  -b, --base-dir BASE_DIR       base directory for the home directory of the
                                new account
  -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
  -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

useradd  普通用户

useradd -g mysql

会建立/home/mysql，赋予密码后可以以该身份登陆。

useradd -r  系统账户

useradd -r mysql

不会建立/home/mysql,可以登陆 但是会提示 没有/home/mysql目录，uid小于500！一般用来管理服务，权限较小，不用来登陆系统！

1.2、userdel

  -f, --force                   force removal of files,
                                even if not owned by user
  -h, --help                    display this help message and exit
  -r, --remove                  remove home directory and mail spool

 默认不删除 /home/username ，加上 -r 则会全部删除。

二、passwd

  -k, --keep-tokens       keep non-expired authentication tokens
  -d, --delete            delete the password for the named account (root only)
  -l, --lock              lock the named account (root only)
  -u, --unlock            unlock the named account (root only)
  -f, --force             force operation
  -x, --maximum=DAYS      maximum password lifetime (root only)
  -n, --minimum=DAYS      minimum password lifetime (root only)
  -w, --warning=DAYS      number of days warning users receives before
                          password expiration (root only)
  -i, --inactive=DAYS     number of days after password expiration when an
                          account becomes disabled (root only)
  -S, --status            report password status on the named account (root
                          only)
  --stdin                 read new tokens from stdin (root only)

 2.1 清空密码

passwd -d username

三、在线用户管理

3.1 查看 w

   -h    skip header
    -l    long listing (default)
    -s    short listing
    -u    ignore uid of processes
    -f    toggle FROM field (default on)
    -V    display version

3.2 踢出

使用命令pkill -kill -t  用户tty

四、直接操作配置文件 

4.1 /etc/passwd

4.2 /etc/group

4.3 /etc/shadow