第四周作業

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 ~]# cp -r /etc/skel/ /home/tuser1
[root@localhost ~]# chmod go= /home/tuser1/ -R
[root@localhost ~]# ll -a /home/tuser1/
total 12
drwx------  3 root root  74 Jun  2 14:27 .
drwxr-xr-x. 8 root root  84 Jun  2 14:27 ..
-rw-------  1 root root  18 Jun  2 14:27 .bash_logout
-rw-------  1 root root 193 Jun  2 14:27 .bash_profile
-rw-------  1 root root 231 Jun  2 14:27 .bashrc
drwx------  4 root root  37 Jun  2 14:27 .mozilla

2.編輯/etc/group文件，添加組hadoop

[root@localhost ~]# vim /etc/group
hadoop:x:2019:

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 ~]# vim /etc/passwd
hadoop:x:2019:2019::/home/hadoop:/bin/bash
[root@localhost ~]# id hadoop
uid=2019(hadoop) gid=2019(hadoop) groups=2019(hadoop)

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 ~]# cp -r /etc/skel/ /home/hadoop 
[root@localhost ~]# chmod go= /home/hadoop/ 
[root@localhost ~]# ll -d /home/hadoop/
drwx------ 3 root root 74 Jun  2 14:40 /home/hadoop/

5.修改/home/hadoop目錄及其內部的所有文件的屬主為hadoop，屬組為hadoop

[root@localhost ~]# chown hadoop:hadoop /home/hadoop/ -R
[root@localhost ~]# ll -a /home/hadoop/
total 16
drwx------   3 hadoop hadoop   74 Jun  2 14:40 .
drwxr-xr-x. 10 root   root   4096 Jun  2 14:40 ..
-rw-r--r--   1 hadoop hadoop   18 Jun  2 14:40 .bash_logout
-rw-r--r--   1 hadoop hadoop  193 Jun  2 14:40 .bash_profile
-rw-r--r--   1 hadoop hadoop  231 Jun  2 14:40 .bashrc
drwxr-xr-x   4 hadoop hadoop   37 Jun  2 14:40 .mozilla

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 ~]# cat /tmp/meminfo |grep -i "^s"
she is a teacher
SwapCached:         5368 kB
SwapTotal:       2097148 kB
SwapFree:        2079808 kB
Shmem:             17648 kB
Slab:             198104 kB
SReclaimable:     146900 kB
SUnreclaim:        51204 kB

[root@localhost ~]# cat /tmp/meminfo |grep -E  "^(S|s)"
she is a teacher
SwapCached:         5368 kB
SwapTotal:       2097148 kB
SwapFree:        2079808 kB
Shmem:             17648 kB
Slab:             198104 kB
SReclaimable:     146900 kB
SUnreclaim:        51204 kB

7.顯示/etc/passwd文件中其默認shell為非/sbin/nologin的用戶

[root@localhost ~]# cat /etc/passwd |grep -v "/sbin/nologin$" |cut -d: -f1 
root
sync
shutdown
halt
zach
test
mageia
slackware
test1
hadoop

8.顯示/etc/passwd文件中其默認shell為/bin/bash的用戶

[root@localhost ~]# cat /etc/passwd |grep "/bin/bash$" |cut -d: -f1 
root
zach
test
mageia
test1
hadoop

9.找出/etc/passwd文件中的一位數或兩位數

[root@localhost ~]# cat /etc/passwd |grep -o -E "\<[0-9]{1,2}\>"

10.顯示/boot/grub2/grub.cfg中以至少一個空白字符開頭的行

[root@localhost ~]# cat /boot/grub2/grub.cfg |grep '^[[:space:]]\+'
  load_env
   set default="${next_entry}"
   set next_entry=
   save_env next_entry
   set boot_once=true
   set default="${saved_entry}"
  menuentry_id_option="--id"
  menuentry_id_option=""
  set saved_entry="${prev_saved_entry}"
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
  if [ -z "${boot_once}" ]; then
    saved_entry="${chosen}"
    save_env saved_entry
  fi
  if [ x$feature_all_video_module = xy ]; then
    insmod all_video
    ......
    ......

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 rc.d]# cat /etc/rc.d/rc.local |grep '^#[[:space:]]\+[^[:space:]]\+'
# 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’后或跟空白字符結尾的行

[root@localhost tmp]# netstat -tan |grep -E '(LISTEN$)|(LISTEN[[:space:]]*$)'
tcp        0      0 0.0.0.0:873             0.0.0.0:*               LISTEN     
tcp        0      0 192.168.122.1:53        0.0.0.0:*               LISTEN     
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:631           0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN     
tcp        0      0 127.0.0.1:25151         0.0.0.0:*               LISTEN     
tcp6       0      0 :::873                  :::*                    LISTEN     
tcp6       0      0 :::80                   :::*                    LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN     
tcp6       0      0 ::1:631                 :::*                    LISTEN     
tcp6       0      0 ::1:25                  :::*                    LISTEN     
tcp6       0      0 :::443                  :::*                    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 tmp]# useradd bash
[root@localhost tmp]# useradd testbash
[root@localhost tmp]# useradd basher
[root@localhost tmp]# useradd -s /sbin/nologin nolgin 
[root@localhost tmp]# cat /etc/passwd |grep "^\(\<.*\>\).*\1$"
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:2020:2020::/home/bash:/bin/bash
nologin:x:2023:2023::/home/nolgin:/sbin/nologin