linux创建用户的本质介绍,linux创建本质
linux创建用户的本质介绍,linux创建本质
ref: useradd命令的参数 /etc/default/useradd配置文件 /etc/skel目录下的文件 手动创建一个用户
useradd命令的参数
[vincent@localhost ~]$ useradd --help -bash: /usr/sbin/useradd: Permission denied [vincent@localhost ~]$ sudo useradd --help [sudo] password for vincent: Usage: useradd [options] LOGIN useradd -D useradd -D [options] Options: -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 # 可以看出,这个参数可以打印添加用户时默认的配置文件 -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 -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 # 查看添加用户时的默认配置 [vincent@localhost ~]$ sudo useradd -D GROUP=100 HOME=/home INACTIVE=-1 EXPIRE= SHELL=/bin/bash SKEL=/etc/skel CREATE_MAIL_SPOOL=yes [vincent@localhost ~]$ sudo useradd -D -s /sbin/nologin # 其实上面输出的结果就是/etc/default/useradd文件里面的内容 ]$ sudo cat /etc/default/useradd # useradd defaults file GROUP=100 HOME=/home INACTIVE=-1 EXPIRE= SHELL=/sbin/nologin SKEL=/etc/skel CREATE_MAIL_SPOOL=yes
/etc/default/useradd配置文件
即useradd -D打印的输出结果的来源
/etc/skel目录下的文件
此目录下的文件会在创建用户时,将此目录下的文件复制至新创建用户的家目录下,前提是这个用户有家目录
目录树如下
[vincent@localhost ~]$ sudo ls -la /etc/skel/ total 24 drwxr-xr-x. 2 root root 59 Mar 22 11:14 . drwxr-xr-x. 74 root root 8192 Mar 22 13:47 .. -rw-r--r--. 1 root root 18 Nov 20 2015 .bash_logout -rw-r--r--. 1 root root 193 Nov 20 2015 .bash_profile -rw-r--r--. 1 root root 231 Nov 20 2015 .bashr
手动创建一个用户
1、创建用户的家目录
$ sudo mkdir /home/annie [sudo] password for vincent:
2、拷贝登录、登出使用的文件于新用户目录
[vincent@localhost ~]$ sudo ls /etc/skel/ -a . .. .bash_logout .bash_profile .bashrc [vincent@localhost ~]$ sudo cp /etc/skel/.bash_logout /etc/skel/.bashrc /etc/skel/.bash_profile /home/annie/
/etc/passwd3、修改相关的配置文件
$ grep annie /etc/passwd annie:x:1001:1001:vincent:/home/annie:/bin/bash/etc/shadow
$ sudo grep annie /etc/shadow annie:$6$PiTiKh9B$Da4VaaR0qlk55r1VFyX3OfQfgj944xExTIdAsyVVTqjmf/u.On8MAfkV0B9RQg5E/OzWj2nYEHGnX.M8feXE3/:17612:0:99999:7:::/etc/group
$ sudo grep annie /etc/group annie:x:1001:annie
4、修改密码,登录测试
[vincent@localhost ~]$ sudo passwd annie Changing password for user annie. New password: BAD PASSWORD: The password is shorter than 8 characters Retype new password: passwd: all authentication tokens updated successfully. [vincent@localhost ~]$ [vincent@localhost ~]$ [vincent@localhost ~]$ su - annie Password: Last failed login: Thu Mar 22 17:26:18 EDT 2018 on pts/1 There was 1 failed login attempt since the last successful login. [annie@localhost ~]$ [annie@localhost ~]$ id uid=1001(annie) gid=1001(annie) groups=1001(annie) [annie@localhost ~]$ who am i vincent pts/1 2018-03-22 17:23 (172.16.81.1) [annie@localhost ~]$ id annie uid=1001(annie) gid=1001(annie) groups=1001(annie) [annie@localhost ~]$ logout
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