1、新建系統組mariadb, 新建系統用戶mariadb, 屬於mariadb組，要求其沒有家目錄，且shell爲/sbin/nologin；嘗試root切換至用戶，查看其命令提示符；
[root@CentOS7-171 ~]# groupadd mariadb [root@CentOS7-171 ~]# useradd mariadb -g mariadb -s /sbin/nologin -M [root@CentOS7-171 ~]# id mariadb uid=4004(mariadb) gid=5002(mariadb) groups=5002(mariadb) [root@CentOS7-171 ~]# su - mariadb Last login: Thu Mar 2 20:51:19 CST 2017 on pts/0 su: warning: cannot change directory to /home/mariadb: No such file or directory This account is currently not available. [root@CentOS7-171 ~]# tail -1 /etc/passwd mariadb:x:4004:5002::/home/mariadb:/sbin/nologin
2、新建GID爲5000的組mageedu，新建用戶gentoo，要求其家目錄爲/users/gentoo，密碼同用戶名；
[root@CentOS7-171 ~]# mkdir /users/ [root@CentOS7-171 ~]# useradd -d /users/gentoo gentoo [root@CentOS7-171 ~]# echo "gentoo" | passwd --stdin gentoo Changing password for user gentoo. passwd: all authentication tokens updated successfully. [root@CentOS7-171 ~]# grep gentoo /etc/passwd gentoo:x:4009:4009::/users/gentoo:/bin/bash
3、新建用戶fedora，其家目錄爲/users/fedora，密碼同用戶名；
[root@CentOS7-171 ~]# useradd -d /users/fedora fedora [root@CentOS7-171 ~]# echo "fedora"|passwd --stdin fedora Changing password for user fedora. passwd: all authentication tokens updated successfully. [root@CentOS7-171 ~]# grep fedora /etc/passwd fedora:x:4010:4010::/users/fedora:/bin/bash
4、新建用戶www, 其家目錄爲/users/www；刪除www用戶，但保留其家目錄；
[root@CentOS7-171 ~]# useradd -d /users/www www [root@CentOS7-171 ~]# grep www /etc/passwd moosefs:x:4008:4008::/users/www:/bin/bash www:x:4011:4011::/users/www:/bin/bash [root@CentOS7-171 ~]# userdel www [root@CentOS7-171 ~]# id www id: www: no such user [root@CentOS7-171 ~]# ll -d /users/www drwx------ 3 4011 4011 74 Mar 2 21:30 /users/www
5、爲用戶gentoo和fedora新增附加組mageedu;
[root@CentOS7-171 ~]# usermod -G mageedu gentoo [root@CentOS7-171 ~]# usermod -G mageedu fedora [root@CentOS7-171 ~]# id gentoo uid=4009(gentoo) gid=4009(gentoo) groups=4009(gentoo),5000(mageedu) [root@CentOS7-171 ~]# id fedora uid=4010(fedora) gid=4010(fedora) groups=4010(fedora),5000(mageedu)
6、複製目錄/var/log至/tmp/目錄，修改/tmp/log及其內部的所有文件的屬組爲mageedu，並讓屬組對目錄本身擁有寫權限；
[root@CentOS7-171 ~]# cp -r /var/log/ /tmp/ [root@CentOS7-171 ~]# ll -d /tmp/log drwxr-xr-x 21 root root 4096 Mar 2 21:34 /tmp/log [root@CentOS7-171 ~]# chown -R :mageedu /tmp/log/ [root@CentOS7-171 ~]# ll -d /tmp/log/ drwxr-xr-x 21 root mageedu 4096 Mar 2 21:34 /tmp/log/ [root@CentOS7-171 ~]# ll /tmp/log/ total 1756 drwxr-xr-x 2 root mageedu 4096 Mar 2 21:34 anaconda drwxr-x--- 2 root mageedu 22 Mar 2 21:34 audit -rw-r--r-- 1 root mageedu 13245 Mar 2 21:34 boot.log [root@CentOS7-171 ~]# chmod g+w /tmp/log/ [root@CentOS7-171 ~]# ll -d /tmp/log/ drwxrwxr-x 21 root mageedu 4096 Mar 2 21:34 /tmp/log/
7、創建用戶gentoo，UID爲4001，基本組爲gentoo，附加組爲distro(GID爲5000)和peguin(GID爲5001)；
[root@CentOS7-171 ~]# groupadd -g 5000 distro [root@CentOS7-171 ~]# groupadd -g 5001 peguin [root@CentOS7-171 ~]# useradd -u 4001 gentoo -G distro,peguin [root@CentOS7-171 ~]# id gentoo uid=4001(gentoo) gid=4001(gentoo) groups=4001(gentoo),5000(distro),5001(peguin)
8、創建用戶fedora，其註釋信息爲"Fedora Core"，默認shell爲/bin/tcsh；
[root@CentOS7-171 ~]# useradd fedora -c "Fedora Core" -s /bin/tcsh [root@CentOS7-171 ~]# id fedora uid=4009(fedora) gid=4009(fedora) groups=4009(fedora) [root@CentOS7-171 ~]# grep fedora /etc/passwd fedora:x:4009:4009:Fedora Core:/home/fedora:/bin/tcsh
9、修改gentoo用戶的家目錄爲/var/tmp/gentoo；要求其原有文件仍能被用戶訪問；
[root@CentOS7-171 ~]# usermod -d /var/tmp/gentoo gentoo [root@CentOS7-171 ~]# grep gentoo /etc/passwd gentoo:x:4001:4001::/var/tmp/gentoo:/bin/bash
10、爲gentoo新增附加組netadmin；
[root@CentOS7-171 ~]# groupadd netadmin [root@CentOS7-171 ~]# usermod -aG netadmin gentoo [root@CentOS7-171 ~]# id gentoo uid=4001(gentoo) gid=4001(gentoo) groups=4001(gentoo),5000(distro),5001(peguin),5003(netadmin)