1、复制/etc/skel目录为/home/tuser1，要求/home/tuser1及其内部文件的属组和其他用户均没有任何访问权限。
[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
总用量 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、编辑/etc/group文件，添加组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、手动编辑/etc/passwd文件新增一行，添加用户hadoop，其基本组ID为hadoop组的id号，其家目录为/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、复制/etc/skel目录为/home/hadoop，要求修改hadoop目录的属组和其他用户没有任何访问权限。
[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目录及其内部所有文件的属主为hadoop，属组为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、显示/proc/meminfo文件中以大写或小写S开头的行，用两种方式。
[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、显示/etc/passwd文件中其默认shell为非/sbin/nologin的用户。
[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、显示/etc/passwd文件中其默认shell为/bin/bash的用户。
[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文件中的一位或两位数。
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、显示/boot/grub/grub.conf中以至少一个空白字符开头的行。
[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、显示/etc/rc.d/rc.sysinit文件中以#开头，后面跟至少一个空白字符，而后又有至少一个非空白字符的行。
[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命令执行结果中，以‘LISTEN’，后跟空白字符结尾的行。
[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、添加用户bash，testbash，basher，nologin（此一个用户的shell为/sbin/nologin），而后找出当前系统上其用户名和默认shell相同的用户信息。
[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