Name: Oracle Linux 上的權限概述 (Permissions Overview on Oracle Linux)
Uploaded: 2025-11-04T15:38:15.000Z
Duration: 8 min 5 s

to 不定詞

In this video, you'll learn about read, write and execute permissions, what it means to be the user owner and group owner of a file or directory, and

在這支影片裡，你會學到讀取、寫入和執行權限，什麼是檔案或目錄的使用者擁有者和群組擁有者，還有

With CHMOD and Chown Linux permissions support three different read, write, and execute.

CHMOD 和 Chown Linux 權限支援三種不同的讀取、寫入和執行。

You'll see these denoted with R, W and X.

你會看到這些用 R、W 和 X 來表示。

Each of these has a different meaning, depending on if it's for a file or a directory.

這些每一個都有不同的意思，取決於是針對檔案還是目錄。

Read for a file means you can view its contents, while for a directory it means you can list the contents and view metadata.

對檔案來說，讀取代表你可以查看它的內容；而對目錄來說，代表你可以列出內容並查看中繼資料。

So if you don't have read permissions, when doing a directory listing, you might see a series of question marks.

所以如果你沒有讀取權限，在進行目錄列表時，你可能會看到一連串的問號。

Write for a file means you can modify its contents, while for directory it means you can create new files within that directory.

對檔案來說，寫入代表你可以修改它的內容；而對目錄來說，代表你可以在該目錄內建立新檔案。

And finally, execute for a file means that you can run it as an application, while for a directory it means you can enter or traverse that directory.

最後，對檔案來說，執行代表你可以將它作為應用程式來運行；而對目錄來說，代表你可以進入或遍歷該目錄。

Let's jump to a terminal and take a look at some examples.

我們來跳到終端機看看一些例子吧。

If I run LS L within this working directory, we see that it has a file and a directory.

如果我們在這個工作目錄下執行 LS L，可以看到有一個檔案和一個目錄。

The permissions are defined by these 10 values.

Let's take a closer look at this first file.

我們來仔細看看這個第一個檔案。

The dash indicates that this is a regular file.

But there are other types, such as D for directory, L for link, B for block, device, and

但還有其他類型，像是 D 代表目錄、L 代表連結、B 代表區塊裝置，

The next three values represent the permissions for the user owner.

接下來的三個值代表使用者擁有者的權限。

The middle three are the group owner and the final three are for other.

中間的三個是群組擁有者，最後三個是給其他人的。

所以是任何不是使用者或群組的人。

Each file or directory has a single user owner and a single group owner.

每個檔案或目錄都有一個使用者擁有者和一個群組擁有者。

As you can see, we have a file called salesreport.txt and and it's owned by the user Michael and belongs to the group Office.

可以看到，我們有一個叫做 salesreport.txt 的檔案，它的擁有者是 Michael，屬於 Office 群組。

So Michael has read, write, and execute permissions.

所以 Michael 擁有讀取、寫入和執行權限。

The Office group has read and execute permissions, and Other has no permissions.

Office 群組擁有讀取和執行權限，其他人則沒有權限。

在這個系統上，有三位使用者。

This is important to keep in mind because we'll be looking at how a user's group affects their access to a file.

這點很重要，因為我們會看看使用者的群組如何影響他們對檔案的存取。

So Michael belongs to the Michael and Office groups, Pam to the Pam and Office groups, and

所以 Michael 屬於 Michael 和 Office 群組，Pam 屬於 Pam 和 Office 群組，

To set up a similar scenario on your system, you can check out the video on Users and groups.

要在你的系統上設定類似的場景，你可以看看關於使用者和群組的影片。

When evaluating permissions, the system processes from left to right and stops at the first match.

在評估權限時，系統會從左到右處理，並在第一個符合的項目停止。

So let's say that Pam wants to read the sales report file.

所以假設 Pam 想讀取 sales report 這個檔案。

It's not Pam, so it'll move to the group which is set to Office Pam belongs to this group, so she would be able to read the sales report file.

不是 Pam，所以它會移到群組，而群組設定是 Office，Pam 屬於這個群組，所以她就能讀取 sales report 檔案。

We can test that by going back to the terminal, switching to the PAM user with SU PAM and then running Cat SalesReport TXT, and

我們可以回到終端機，用 SU PAM 切換到 PAM 使用者，然後執行 Cat SalesReport TXT 來測試，

She's not part of the Office group, so the other permissions would apply to her.

她不屬於 Office 群組，所以其他權限就會適用於她。

And as a result she wouldn't be able to read the file.

If we switch to the Jan user with SU Jan and try the same thing with Cat salesreport.

如果我們用 SU Jan 切換到 Jan 使用者，並嘗試用 Cat salesreport 做同樣的事。

Let's take a look at changing permissions for a file.

我們來看看如何修改檔案的權限。

I'll go back to the Michael user with SU Michael and create a blank file using touch a space and then the name of a new file.

我會用 SU Michael 切換回 Michael 使用者，然後用 touch 指令建立一個空白檔案，後面接著新檔案的名稱。

Then we'll run LS l to look at the details for that file.

接著我們執行 LS l 來查看該檔案的詳細資訊。

By default, the user in group is whoever created the file, in this case michael and the read, write, execute permissions will also be set to a default value.

預設的使用者和群組是建立檔案的人，在這個例子中是 michael，而讀取、寫入、執行權限也會設定為預設值。

This is based on your umask, which is more than we want to get into here.

這取決於你的 umask，這部分我們就不深入探討了。

But just know that the file gets created with default permissions.

但只要知道檔案建立時會有預設權限就好。

To change permissions for this file, we can use the chmod command.

要修改這個檔案的權限，我們可以使用 chmod 指令。

The syntax is chmod a space and the options a space, permissions, a space, and the file name.

語法是 chmod 空格 選項 空格 權限 空格 檔案名稱。

We can define the permissions in two ways, either numerically or symbolically.

我們可以透過兩種方式來定義權限，一種是數字，另一種是符號。

We'll start by looking at the symbolic method.

As we noted earlier, there's a user group and other, so we can set permissions using u, g, and

就像我們前面提到的，有使用者、群組和其他人，所以我們可以結合 u、g 和

o，以及 rwx 這幾個值來設定權限。

Let's jump back to the terminal and take a look at an example.

我們回到終端機來看看一個範例。

I'll need root privileges to alter the permissions, so I'll use sudo then chmod and let's give the user read and execute permissions, which would be u, r x.

我需要 root 權限來修改權限，所以會用 sudo 然後是 chmod，接著我們給使用者讀取和執行權限，也就是 u, r x。

Then we'll use a comma and set the group permissions to read, write, and execute.

然後我們用逗號，設定群組權限為讀取、寫入和執行。

So g rwx and for other I don't want any permissions, so we'll use a comma and then o equals with nothing after it, then a space and the file name running LS l we can see it did change the permissions.

所以是 g rwx，至於其他人，我不想給任何權限，所以我們用逗號，然後是 o 等於後面什麼都沒有，接著是空格和檔案名稱，執行 ls -l 我們可以看到權限確實改變了。

The nice thing about the symbolic method is that you can add or remove permissions without worrying about what the current permissions are.

符號方式的好處是，你可以新增或移除權限，而不用擔心目前的權限是什麼。

所以我們用 sudo chmod 來試試看。

Then to add write permissions for both the user and other, I can group u and o together and then do w and let's take away write from the group.

接著，如果我想要為使用者和其他人新增寫入權限，我可以把 u 和 o 組合起來，然後加上 w，並且移除群組的寫入權限。

So I'll use comma, then g W, a space and the file name.

所以，我會用逗號，接著是 g W，然後是空格和檔案名稱。

Using LS L, we can confirm the permissions changed.

使用 LS L，我們可以確認權限已經改變了。

The other method for defining permissions is numerical, where we assign a value to each permission and add the numbers together to get the final result.

定義權限的另一種方法是使用數字，我們會為每個權限指派一個值，然後將數字加總得到最終結果。

Read has a value of 4, write 2 and execute 1.

讀取的值是 4，寫入是 2，執行是 1。

So for read, write execute it, it would be 4, 2, 1 for a total of 7.

所以，讀取、寫入、執行，就是 4、2、1，總共是 7。

Read and execute would be 4, 1, for a total of 5.

讀取和執行是 4、1，總共是 5。

So the current permissions for this file would be 7, 5, 2.

所以，這個檔案目前的權限會是 7、5、2。

Let's go back to the terminal and try changing the permissions numerically.

讓我們回到終端機，試著用數字來改變權限。

Maybe we want to set the permissions to read and execute for the user, read, write, and

也許我們想設定使用者擁有讀取和執行權限，群組擁有讀取、寫入和執行權限，而其他人則沒有權限。

execute for the group, and no permissions for other.

設定使用者擁有的權限比群組少，像這樣的情況比較少見。

Setting the user to have less permissions than the group, like this is uncommon.

但我這麼做是為了指出一個容易被忽略的地方，

But I've done it here to point out something that's easily overlooked, and

所以我們會輸入 sudo chmod 570 加上檔案名稱。

So we'll do sudo chmod570 and the file name.

然後執行 ls -l，我們就會看到這個改變。

讓我們用 Michael 這個使用者來測試這些權限。

Let's test these permissions with the Michael user.

Michael 同時是使用者和群組的擁有者。

Michael is both the user and group owner.

所以你可能會認為，因為他是 Michael 群組的一員，他應該可以讀取、寫入和執行。

So you might think he should be able to read, write and execute before because he's part of the Michael group.

But remember that the system processes permissions from left to right and stops at the first match.

但請記得，系統處理權限是從左到右，遇到第一個符合的就會停下來。

So it checks to see if Michael is the user he is.

所以它會檢查 Michael 是不是使用者本人。

So it stops there and only grants him read and execute permissions.

所以它在這裡就停住了，只給他讀取和執行的權限。

We can test this by trying to edit the file with vi a space and the file name.

我們可以試著用 vi 加上檔案名稱來編輯這個檔案，來測試看看。

And if we try to make changes, it gives us a warning.

如果我們試著做修改，它就會給我們一個警告。

What if we want to change the user owner and group owner for this file?

那如果我們想要改變這個檔案的使用者擁有者和群組擁有者呢？

我們可以透過 chown 這個指令來做到。

The syntax is chown a space, any options, a space, the username, a colon, group name, a space, and

語法是 chown 加上任何選項，然後是使用者名稱，冒號，群組名稱，

We need root privileges to run this, so sudo chown.

我們需要 root 權限才能執行，所以 sudo chown。

Then we specify the user, a colon, the group followed by a space and the file name.

接著我們指定使用者、冒號、群組，然後是空格和檔案名稱。

Using LS l shows us that the user is now Pam and the group is office.

使用 LS l 指令，可以看到使用者現在是 Pam，群組是 office。

If we want to just change the user, we do that by only specifying a user and leaving off the colon and group name.

如果我們只想改變使用者，可以只指定使用者，省略冒號和群組名稱。

For example, I can do sudo chown jan clientlist.

例如，我可以執行 sudo chown jan clientlist。

Sure enough, LS l shows us that the user has changed to jan.

果然，LS l 指令顯示使用者已變更為 jan。

We can change only the group with sudo chown a colon, the group name, and the filename.

我們可以只變更群組，使用 sudo chown，後接冒號、群組名稱和檔案名稱。

And finally, if we run LS L, we see that change.

最後，如果我們執行 LS L，就能看到這個變更。

That's it for a quick overview of permissions on a Linux system.

這就是關於 Linux 系統權限的快速概覽。

I hope it gives you a basic understanding of how the read, write and execute permissions affect access to a file or directory.

希望這能讓你對讀取、寫入和執行權限如何影響檔案或目錄的存取有基本的瞭解。

字幕列表影片播放

Oracle Linux 上的權限概述 (Permissions Overview on Oracle Linux)

scenario

access

combination

represent