1、復制/etc/skel目錄為/home/tuser1，要求/home/tuser1及其內部文件的屬組和其他用戶均沒有任何訪問權限。
[root@localhost home]# cp -R /etc/skel/ /home/tuser1 && chmod -R g=,o= /home/tuser1 
[root@localhost home]# ll -d /home/tuser1/
drwx——. 2 root root 59 3月   7 20:30 /home/tuser1/
[root@localhost tuser1]# ll -a
總用量 16
drwx——.  2 root root   59 3月   7 20:30 .
drwxr-xr-x. 15 root root 4096 3月   7 20:30 ..
-rw——-.  1 root root   18 3月   7 20:30 .bash_logout
-rw——-.  1 root root  193 3月   7 20:30 .bash_profile
-rw——-.  1 root root  231 3月   7 20:30 .bashrc

2、編輯/etc/group文件，添加組hadoop。
[root@localhost tuser1]# echo ‘hadoop:x:5005:’ >> /etc/group
[root@localhost tuser1]# tail -2 /etc/group
admins:x:5004:slackware
hadoop:x:5005:

3、手動編輯/etc/passwd文件新增一行，添加用戶hadoop，其基本組ID為hadoop組的id號，其家目錄為/home/hadoop。
[root@localhost tuser1]# vim /etc/passwd
mageia:x:1100:1100::/home/linux:/bin/bash
slackware:x:2002:2016::/home/slackware:/bin/tcsh
hadoop:x:5005:5005::/home/hadoop:/bin/bash
[root@localhost tuser1]# tail -1 /etc/passwd
hadoop:x:5005:5005::/home/hadoop:/bin/bash

4、復制/etc/skel目錄為/home/hadoop，要求修改hadoop目錄的屬組和其他用戶沒有任何訪問權限。
[root@localhost tuser1]# cp -R /etc/skel/ /home/hadoop && chmod g=,o= /home/hadoop
[root@localhost tuser1]# ll -d /home/hadoop/
drwx——. 2 root root 59 3月   7 20:51 /home/hadoop/

5、修改/home/hadoop目錄及其內部所有文件的屬主為hadoop，屬組為hadoop。
[root@localhost tuser1]# cd ..
[root@localhost home]# chown -R hadoop:hadoop /home/hadoop/
[root@localhost home]# ll -d /home/hadoop/
drwx——. 2 hadoop hadoop 59 3月   7 20:51 /home/hadoop/

6、顯示/proc/meminfo文件中以大寫或小寫S開頭的行，用兩種方式。
[root@localhost home]# grep  ‘^[sS]’ /proc/meminfo   
SwapCached:            0 kB
SwapTotal:       2097148 kB
SwapFree:        2097148 kB
Shmem:              6868 kB
Slab:              56628 kB
SReclaimable:      21584 kB
SUnreclaim:        35044 kB  
[root@localhost home]# grep -v ‘^[^sS]’ /proc/meminfo 
SwapCached:            0 kB
SwapTotal:       2097148 kB
SwapFree:        2097148 kB
Shmem:              6868 kB
Slab:              56644 kB
SReclaimable:      21584 kB
SUnreclaim:        35060 kB
7、顯示/etc/passwd文件中其默認shell為非/sbin/nologin的用戶。
[root@localhost home]# grep -v ‘/sbin/nologin$’ /etc/passwd
root:x:0:0:root:/root:/bin/bash
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
gentoo:x:4001:5002::/var/tmp/gentoo:/bin/bash
fedora:x:4002:4002:Fedora Core:/home/fedora:/bin/tcsh
abc:x:4003:4003::/home/abc:/bin/bash
centos:x:4004:4004::/home/centos:/bin/bash
user1:x:4005:4005::/home/user1:/bin/bash
bash:x:4006:4006::/home/bash:/bin/bash
testbash:x:4007:4007::/home/testbash:/bin/bash
basher:x:4008:4008::/home/basher:/bin/bash
mageia:x:1100:1100::/home/linux:/bin/bash
slackware:x:2002:2016::/home/slackware:/bin/tcsh
hadoop:x:5005:5005::/home/hadoop:/bin/bash

8、顯示/etc/passwd文件中其默認shell為/bin/bash的用戶。
[root@localhost home]# grep ‘/bin/bash$’ /etc/passwd
root:x:0:0:root:/root:/bin/bash
gentoo:x:4001:5002::/var/tmp/gentoo:/bin/bash
abc:x:4003:4003::/home/abc:/bin/bash
centos:x:4004:4004::/home/centos:/bin/bash
user1:x:4005:4005::/home/user1:/bin/bash
bash:x:4006:4006::/home/bash:/bin/bash
testbash:x:4007:4007::/home/testbash:/bin/bash
basher:x:4008:4008::/home/basher:/bin/bash
mageia:x:1100:1100::/home/linux:/bin/bash
hadoop:x:5005:5005::/home/hadoop:/bin/bash

9、找出/etc/passwd文件中的一位或兩位數。
sshd:x:74:74:Privilege-separated SSH:/var/empty/sshd:/sbin/nologin
[root@localhost home]# grep ‘\<[[:digit:]]{1,2}\>’ /etc/passwd 
root:x:0:0:root:/root:/bin/bash
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
adm:x:3:4:adm:/var/adm:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/spool/mail:/sbin/nologin

10、顯示/boot/grub/grub.conf中以至少一個空白字符開頭的行。
[root@localhost home]# grep ‘^[[:space:]]+’ /boot/grub2/grub.cfg 
 load_env
  set default=”${next_entry}”
  set next_entry=
  save_env next_entry
  set boot_once=true
  set default=”${saved_entry}”

11、顯示/etc/rc.d/rc.sysinit文件中以#開頭，后面跟至少一個空白字符，而后又有至少一個非空白字符的行。
[root@localhost home]# grep ‘^#[[:space:]]+.*[^[:space:]]+’ /etc/rc.d/rc.local 

THIS FILE IS ADDED FOR COMPATIBILITY PURPOSES

It is highly advisable to create own systemd services or udev rules

to run scripts during boot instead of using this file.

In contrast to previous versions due to parallel execution during boot

this script will NOT be run after all other services.

Please note that you must run ‘chmod +x /etc/rc.d/rc.local’ to ensure

that this script will be executed during boot.

12、打出netstat -tan命令執行結果中，以‘LISTEN’，后跟空白字符結尾的行。
[root@localhost home]# netstat -tan | grep ‘LISTEN[[:space:]]\>’ 
tcp        0      0 0.0.0.0:22              0.0.0.0:               LISTEN     
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN     
tcp6       0      0 ::1:25                  :::*                    LISTEN  
   
13、添加用戶bash，testbash，basher，nologin（此一個用戶的shell為/sbin/nologin），而后找出當前系統上其用戶名和默認shell相同的用戶信息。
[root@localhost home]# grep -E ‘(^[^:]+\>).*\1$’ /etc/passwd 
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
bash:x:4006:4006::/home/bash:/bin/bash
nologin:x:4009:4009::/home/nologin:/sbin/nologin