5. 基礎權限設定

題目：
1. Create a file called yak and display the file permissions.
2. Devise a command to set the following permission on yak.
    a. the owner has read and write privileges.
    b. group members have read-only privileges.
    c. others cannot access the file at all.

3. Execute the command devised above and observe the effect.
4. Execute a command that would revoke read privileges from the group on yak.
5. Execute the command devised above and observe the effect.

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solution：
1. 建立檔案名為yak
[hhh@station8 ~]$ touch yak  
[hhh@station8 ~]$ ls -l
總計 1
-rw-rw-r-- 1 hhh hhh 0  2月 23 20:57 yak

2. 更改yak的權限設定，以符合題目的要求。
[hhh@station8 ~]$ chmod 640 yak
[hhh@station8 ~]$ ls -l
總計 1
-rw-r----- 1 hhh hhh 0  2月 23 20:57 yak

3. 依據題目要求，修正 group 的權限。
[hhh@station8 ~]$ chmod 600 yak
[hhh@station8 ~]$ ls -l
總計 1
-rw------- 1 hhh hhh 0  2月 23 20:57 yak