修改shell 将当前shell（默认是bash B SHELL ）改为csh C SHELL

切换用户：su
[root@node203 ~]# su - linsco   //由超级管理员用户切换成普通用户

[linsco@node203 ~]$ su root   
 [linsco@node203 ~]$ su -         //由普通用户切换成超级管理员用户
Password:

查看用户的UID，GID
[root@node203 home]# id root
uid=0(root) gid=0(root) groups=0(root),1(bin),2(daemon),3(sys),4(adm),6(disk),10(wheel)
[root@node203 home]# id linsco
uid=501(linsco) gid=501(linsco) groups=501(linsco)

用户分为：root用户，虚拟用户和普通用户
检查用户身份：
who:查询当前在线的用户
groups :查询当前用户所属的组
id:显示当前用户的信息
finger:查询用户信息
whoami：显示当前用户
w:查询当前用户的信息

/etc/passwd //是系统识别用户的一个文件
root:x:0:0:rsc,runhow,0592-5213966,15932836339:/root:/bin/bash
rscpass:x:100:507:ruanshengchang,runhow health,18859224109,18859224109:/home/rscpass:/bin/bash
root：用户名
x:   用户的密码，X表示密码被映射到/etc/shadow文件中
100:标识用户的UID,root的UID为0
 查看UID最大值：/etc/login.defs
 如果将别的用户的UID修改为0，那么此用户就有root的权限
507:组群标识号
:/home/rscpass:用户宿主目录
:/bin/bash:用户使用的shell

Usage: passwd [OPTION...] <accountName>
  -k, --keep-tokens       keep non-expired authentication tokens
  -d, --delete            delete the password for the named account (root only)  //删除密码   -d 用户名,不要密码就可以进入
  -l, --lock              lock the named account (root only)               //暂时锁定指定的用户账户
  -u, --unlock            unlock the named account (root only)         //解除锁定
  -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    //显示用户的状态 
                          only)
  --stdin                 read new tokens from stdin (root only)

Help options:
  -?, --help              Show this help message
  --usage                 Display brief usage message

/etc/shadow    //所有系统用户密码文件
root:$1$qwzTSMfi$U3F3sK6/X9FsKuk8DdqD5.:15388:0:99999:7:::
rscpass:$1$pIPEe9Vn$0f1eKKi5TPzb6Rr.lY8Mi/:15389::::::
rpc:!!:15388:0:99999:7:::

rscpass:用户名，与/etc/passwd的用户名相同
$1$pIPEe9Vn$0f1eKKi5TPzb6Rr.lY8Mi:加密的密码
!!:代表此用户不能登录
!qewadfxcvweadsf:以!开头的用户已锁定
*:代表

useradd - create a new user or update default new user information

authconfig  更改密码的存放方式

添加用户；
 #useradd tond  //添加用户
 #passwd tond  //设置密码
系统添加用户的标准步骤
编辑/etc/passwd与/etc/group
创建用户主目录
从/etc/skel拷贝文件与目录
让新用户获得其主目录与文件的拥有权限
组新用户一个密码
设置用户UID
 #useradd -u 550 tong
 #useradd -G root tong
 -u:设置UID
 -d:设置用户宿主目录,不是系统的目录/home/
 -g:设置属于那个组
 -s:设置shell类型      禁止用户登陆/sbin/nologin
 -n:禁止系统建立与用户名同名的用户组
 -l:参数设置用户名
 -e:禁用账号的日期,YYYY-MM-DD
 -f:天数 口令过期后，帐号禁用前的天数
 -M,                       do not create user‘s home directory(overrides /etc/login.defs)
  -m, --create-home             create home directory for the new user
  -r,                       create system account
修改用户帐户：
 usermod -d /home/kkk  tond
 -d:修改宿主目录
 -i:修改用户帐号名称
 -L:锁定用户密码，使其无效
 Options:
  -a, --append                  append the user to the supplemental GROUPS
                                (use only with -G)
  -c, --comment COMMENT         new value of the GECOS field   //设定用户全名,用finger查看   usermod -c ‘***‘ 用户名
  -d, --home HOME_DIR           new home directory for the user account //更改用户的家目录
  -e, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE //设定用户密码过期时间
   eg:usermod -e "2009-01-01" linsco
  -f, --inactive INACTIVE       set password inactive after expiration
                                to INACTIVE //设置密码过期后多久就关闭这个帐号
  -g, --gid GROUP               force use GROUP as new primary group  //更改用户的GID
   eg:[root@node203 home]# usermod -g root rsc  //修改用户rsc的GID
   eg:[root@node203 home]# usermod -g 503 rsc  //修改用户rsc的GID  不能修改加入不存在的组
  -G, --groups GROUPS           new list of supplementary GROUPS //将用户添加组里面
   eg:# usermod -G root rsc //将rsc用户加入到root组中  #id rsc 查看
  -h, --help                    display this help message and exit
  -l, --login NEW_LOGIN         new value of the login name
  -L, --lock                    lock the user account //锁定用户
  -m, --move-home               move contents of the home directory to the new
                                location (use only with -d)
  -o, --non-unique              allow using duplicate (non-unique) UID
  -p, --password PASSWORD       use encrypted password for the new password
  -s, --shell SHELL             new login shell for the user account  //更改用户默认使用的SHELL
   eg:# usermod -s /bin/csh rsc
  -u, --uid UID                 new UID for the user account //更改用户的UID
   eg:# usermod -u 503 rsc
  -U, --unlock                  unlock the user account//解除用户锁定   查看用户是否锁定：# passwd -S rsc
  -Z, --selinux-user    new selinux user mapping for the user account
eg:
#useradd -u 600 -g tom -G boobooke zl
新建用户zl,设定uid为600,初始群组为tom,加入到boobooke群组中
#useradd gmy1 -s /bin/csh

userdel [-r] [用户名]//删除或禁止用户帐户
Options:
  -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  //删除用户时，一起删除用户家目录
eg:
 userdel -r tond

Pwck//校验用户配置文件/etc/passwd和/etc/shadow内容是否合法,完整
[root@localhost ~]# pwck
user adm: directory /var/adm does not exist
user news: directory /etc/news does not exist
user uucp: directory /var/spool/uucp does not exist
user gopher: directory /var/gopher does not exist
user pcap: directory /var/arpwatch does not exist
user sabayon: directory /home/sabayon does not exist
user gaga: no group 510
user gaga: directory /home/gaga does not exist
pwck: no changes

chage //管理用户口令的进效

Usage: chage [options] user 
  选项   用户名
Options:
  -d, --lastday LAST_DAY        set last password change to LAST_DAY
  -E, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE
  -h, --help                    display this help message and exit
  -I, --inactive INACTIVE       set password inactive after expiration
                                to INACTIVE
  -l, --list                    show account aging information
  -m, --mindays MIN_DAYS        set minimum number of days before password
                                change to MIN_DAYS
  -M, --maxdays MAX_DAYS        set maximim number of days before password
                                change to MAX_DAYS
  -W, --warndays WARN_DAYS      set expiration warning days to WARN_DAYS
组 管 理 
/etc/group    //系统用户所在的组
格式：group_name:passwd:GID:user_list
root:x:0:root
root:用户组名称 
X:已设置密码
0:组群号
root:组群成员

/etc/gshadow    //是etc/group的加密信息文件
root:::root
daemon:x::root,bin,daemon
jishubu:!::
root：组群名称
!:没有设置密码
root,bin,daemon:组的成员
Groupadd [-g gid [-o] ] [-f]  [组群名]
Options:
  -f, --force                   force exit with success status if the specified
                                group already exists
  -r,                       create system account
  -g, --gid GID                 use GID for the new group    // groupadd -g 5600 test
  -h, --help                    display this help message and exit
  -K, --key KEY=VALUE           overrides /etc/login.defs defaults
  -o, --non-unique              allow create group with duplicate //可以指定不唯一的组ID值，与-g一起使用
                                (non-unique) GID
eg:
 groupadd hello
 groupadd -g 800 hello
 
Groupmod [-g<组群识别码> <-o>] [-n 新组群名称] [组群名称]
groupmod [-g gid [-o]] [-n name] group
-g GID  组ID值
-n 组群名                 更改组名  
-o, --non-unique              allow create group with duplicate //可以指定不唯一的组ID值，与-g一起使用
eg:
 
[root@localhost home]# groupmod -g 509 hello
[root@localhost home]# cat /etc/group | grep hello
hello:x:509:

[root@localhost home]# groupadd -r systems
[root@localhost home]# cat /etc/group | grep systems
systems:x:102:
eg:将tom群组名修改为jack
#groupmod -n jack tom
Groupdel [组群名称]
eg:
 groupdel hello

Gpasswd//设置组群的密码,一般不设置密码
初始用户群组，有效用户群组
初始用户群组:在新建用户或群组时，默认建立与用户名相同的群组名
有效用户群组：通过newgrp修改过的群组名
Usage: gpasswd [-r|-R] group
       gpasswd [-a user] group
       gpasswd [-d user] group
       gpasswd [-A user,...] [-M user,...] group

eg:
 gpasswd -a rscpass root //将rscpass用户加入到root组中
 gpasswd -d rscpass root 
 [root@localhost ~]# gpasswd rscpass  //设置组群密码
 [root@localhost ~]# gpasswd -r rscpass//取消密码
mygroup:x:513:  //没有设置密码
test:$1$48IgiHfr$H48yG/UdLGkOGGaF3GjN20:5600:  //设置了密码
newgrp//以另一个组群的身份登录,前题是一个用户属于多个组才可以
Usage: newgrp [-] [group]
eg:
 newgrp [组群名] 
 newgrp rscpass

groups//显示指定用户的组群成员身份
groups [用户名]
eg:
 groups root //显示root属于那几个组
[root@localhost ~]# groups root
root : root bin daemon sys adm disk wheel
id//显示用户的ID以及所属组群的ID
id[选项] [用户名]
Usage: id [OPTION]... [USERNAME]
Print information for USERNAME, or the current user.
  -a              ignore, for compatibility with other versions
  -Z, --context   print only the context of the current process
  -g, --group     print only the effective group ID
  -G, --groups    print all group IDs
  -n, --name      print a name instead of a number, for -ugG
  -r, --real      print the real ID instead of the effective ID, with -ugG
  -u, --user      print only the effective user ID
      --help     display this help and exit
      --version  output version information and exit
Without any OPTION, print some useful set of identified information.
eg:
 id rscpass
 id -g rscpass
 id -u rscpass
W //详细查询已登录当前系统的用户
[root@localhost ~]# w --help
w: invalid option -- -
usage: w -hlsufV [user]
    -h    skip header
    -l    long listing (default)
    -s    short listing
    -u    ignore uid of processes
    -f    toggle FROM field (default on)
    -V    display version

Who//显示已登录当前计算机用户的简单信息
[root@localhost ~]# who --help
Usage: who [OPTION]... [ FILE | ARG1 ARG2 ]

  -a, --all         same as -b -d --login -p -r -t -T -u
  -b, --boot        time of last system boot
  -d, --dead        print dead processes
  -H, --heading     print line of column headings
  -l, --login       print system login processes
      --lookup      attempt to canonicalize hostnames via DNS
  -m                only hostname and user associated with stdin
  -p, --process     print active processes spawned by init
  -q, --count       all login names and number of users logged on
  -r, --runlevel    print current runlevel
  -s, --short       print only name, line, and time (default)
  -t, --time        print last system clock change
  -T, -w, --mesg    add user‘s message status as +, - or ?
  -u, --users       list users logged in
      --message     same as -T
      --writable    same as -T
      --help     display this help and exit
      --version  output version information and exit

Chsh//改变用户的shell类型
[root@localhost ~]# chsh --help
Usage: chsh [ -s shell ] [ --list-shells ] [ --help ] [ --version ]  [ username ]
 eg:
  chsh  -s /bin/ksh   root 

Su//切换用户帐户进行登录
  -, -l, --login               make the shell a login shell
  -g --group=group             specify the primary group
  -G --supp-group=group        specify a supplemental group
  -c, --commmand=COMMAND       pass a single COMMAND to the shell with -c
  --session-command=COMMAND    pass a single COMMAND to the shell with -c
                               and do not create a new session
  -f, --fast                   pass -f to the shell (for csh or tcsh)
  -m, --preserve-environment   do not reset environment variables
  -p                           same as -m
  -s, --shell=SHELL            run SHELL if /etc/shells allows it
      --help     display this help and exit
      --version  output version information and exit

/etc/skel目录
新建用户的初始化目录,当新建一个用户，这个目录下的所有文件将复制到新建用户的宿主目录下

/etc/login.defs配置文件
是新用户的一些默认设置

/etc/default/useradd 
使用useradd命令的一些规则文件

创建帐户
1.直接修改帐户配置文件来创建帐户
2.执行pwconv来让/etc/passwd和etc/shadow同步

创建组
1.直接修改组帐户配置文件来创建组帐户
2.执行grpconv来让/etc/group和etc/gshadow同步

1.newusers

newusers [input] 批量导入按/etc/passwd格式的文件

创建userfile.txt

2.chpasswd //批量更新用户密码工具

创建userpwdfile.txt

3.pwconv

eg:
 newusers  userfile.txt
 chpasswd < userpwdfile.txt
 pwconv

finger//查找并显示用户
finger [选项]  [用户名]
[root@localhost ~]# finger --help
finger: invalid option -- -
usage: finger [-lmps] [login ...]