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Xingyu.Wang
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How To Find Files Based On their Permissions
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======
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Finding files in Linux is not a big deal. There are plenty of free and open source graphical utilities available on the market. In my opinion, finding files from command line is much easier and faster. We already knew how to [**find and sort files based on access and modification date and time**][1]. Today, we will see how to find files based on their permissions in Unix-like operating systems.
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For the purpose of this guide, I am going to create three files namely **file1** , **file2** and **file3** with permissions **777** , **766** , **655** respectively in a folder named **ostechnix**.
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```
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mkdir ostechnix && cd ostechnix/
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```
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```
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install -b -m 777 /dev/null file1
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```
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```
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install -b -m 766 /dev/null file2
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```
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```
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install -b -m 655 /dev/null file3
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```
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[![][2]][3]
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Now let us find the files based on their permissions.
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### Find files Based On their Permissions
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The typical syntax to find files based on their permissions is:
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```
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find -perm mode
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```
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The MODE can be either with numeric or octal permission (like 777, 666.. etc) or symbolic permission (like u=x, a=r+x).
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Before going further, we can specify the MODE in three different ways.
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1. If we specify the mode without any prefixes, it will find files of **exact** permissions.
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2. If we use **" -"** prefix with mode, at least the files should have the given permission, not the exact permission.
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3. If we use **" /"** prefix, either the owner, the group, or other should have permission to the file.
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Allow me to explain with some examples, so you can understand better.
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First, we will see finding files based on numeric permissions.
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### Find Files Based On their Numeric (octal) Permissions
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Now let me run the following command:
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```
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find -perm 777
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```
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This command will find the files with permission of **exactly 777** in the current directory.
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[![][2]][4]
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As you see in the above output, file1 is the only one that has **exact 777 permission**.
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Now, let us use "-" prefix and see what happens.
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```
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find -perm -766
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```
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[![][2]][5]
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As you see, the above command displays two files. We have set 766 permission to file2, but this command displays two files, why? Because, here we have used "-" prefix". It means that this command will find all files where the file owner has read/write/execute permissions, file group members have read/write permissions and everything else has also read/write permission. In our case, file1 and file2 have met this criteria. In other words, the files need not to have exact 766 permission. It will display any files that falls under this 766 permission.
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Next, we will use "/" prefix and see what happens.
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```
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find -perm /222
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```
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[![][2]][6]
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The above command will find files which are writable by somebody (either their owner, or their group, or anybody else). Here is another example.
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```
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find -perm /220
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```
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This command will find files which are writable by either their owner or their group. That means the files **don 't have to be writable** by **both the owner and group** to be matched; **either** will do.
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But if you run the same command with "-" prefix, you will only see the files only which are writable by both owner and group.
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```
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find -perm -220
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```
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The following screenshot will show you the difference between these two prefixes.
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[![][2]][7]
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Like I already said, we can also use symbolic notation to represent the file permissions.
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Also read:
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### Find Files Based On their Permissions using symbolic notation
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In the following examples, we use symbolic notations such as **u** ( for user), **g** (group), **o** (others). We can also use the letter **a** to represent all three of these categories. The permissions can be specified using letters **r** (read), **w** (write), **x** (executable).
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For instance, to find any file with group **write** permission, run:
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```
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find -perm -g=w
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```
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[![][2]][8]
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As you see in the above example, file1 and file2 have group **write** permission. Please note that you can use either "=" or "+" for symbolic notation. It doesn't matter. For example, the following two commands do the same thing.
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```
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find -perm -g=w
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find -perm -g+w
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```
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To find any file which are writable by the file owner, run:
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```
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find -perm -u=w
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```
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To find any file which are writable by all (the file owner, group and everyone else), run:
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```
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find -perm -a=w
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```
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To find files which are writable by **both** their **owner** and their **group** , use this command:
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```
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find -perm -g+w,u+w
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```
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The above command is equivalent of "find -perm -220" command.
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To find files which are writable by **either** their **owner** or their **group** , run:
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```
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find -perm /u+w,g+w
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```
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Or,
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```
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find -perm /u=w,g=w
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```
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These two commands does the same job as "find -perm /220" command.
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For more details, refer the man pages.
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```
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man find
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```
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Also, check the [**man pages alternatives**][9] to learn more simplified examples of any Linux command.
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And, that's all for now folks. I hope this guide was useful. More good stuffs to come. Stay tuned.
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Cheers!
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--------------------------------------------------------------------------------
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via: https://www.ostechnix.com/find-files-based-permissions/
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作者：[][a]
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译者：[译者ID](https://github.com/译者ID)
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校对：[校对者ID](https://github.com/校对者ID)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
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[a]:https://www.ostechnix.com
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[1] https://www.ostechnix.com/find-sort-files-based-access-modification-date-time-linux/
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[2] data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
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[3] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-1-1.png ()
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[4] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-2.png ()
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[5] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-3.png ()
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[6] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-6.png ()
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[7] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-7.png ()
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[8] http://www.ostechnix.com/wp-content/uploads/2017/12/find-files-8.png ()
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[9] https://www.ostechnix.com/3-good-alternatives-man-pages-every-linux-user-know/
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@ -0,0 +1,170 @@
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根据权限查找文件
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======
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在 Linux 中查找文件并不是什么大问题。市面上也有很多可靠的免费开源可视化的查询工具。但对我而言，查询文件，用命令行的方式会更快更简单。我们已经知道 [ 如何根据访问、修改文件时间寻找或整理文件 ][1]。今天，在基于 Unix 的操作系统中，我们将见识如何通过权限查询文件。
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本段教程中，我将创建三个文件名为 **file1**，**file2** 和 **file3** 分别赋予 **777**，**766** 和 **655** 文件权限，并分别置于名为 **ostechnix** 的文件夹中。
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```
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mkdir ostechnix && cd ostechnix/
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```
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```
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install -b -m 777 /dev/null file1
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```
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```
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install -b -m 766 /dev/null file2
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```
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```
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install -b -m 655 /dev/null file3
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```
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![][3]
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现在，让我们通过权限来查询一下文件。
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### 根据权限查询文件
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根据权限查询文件最具代表性的语法：
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```
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find -perm mode
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```
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MODE 可以是代表权限的八进制数字（777，666…）也可以是权限符号（u=x，a=r+x）。
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在深入之前，我们就以下三点详细说明 MODE 参数。
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1. 如果我们不指定任何参数前缀，它将会寻找 **具体** 权限的文件。
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2. 如果我们使用 **“-”** 参数前缀， 寻找到的文件至少拥有 mode 所述的权限，而不是具体的权限（大于或等于此权限的文件都会被查找出来）。
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3. 如果我们使用 **“/”** 参数前缀，那么所有者、组或者其他人任意一个应当享有此文件的权限。
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为了让你更好的理解，让我举些例子。
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首先，我们将要看到基于数字权限查询文件。
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### 基于数字（八进制）权限查询文件
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让我们运行下列命令：
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```
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find -perm 777
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```
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这条命令将会查询到当前目录权限为 **确切为 777** 权限的文件。
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![1][4]
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当你看见屏幕输出行时，file1 是唯一一个拥有 **确切为 777 权限** 的文件。
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现在，让我们使用 “-” 参数前缀，看看会发生什么。
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```
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find -perm -766
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```
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![][5]
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如你所见，命令行上显示两个文件。我们给 file2 设置了 766 权限，但是命令行显示两个文件，什么鬼？因为，我们设置了 “-” 参数前缀。它意味着这条命令将在所有文件中查询文件所有者的 读/写/执行 权限，文件用户组的 读/写权限和其他用户的 读/写 全西安。本例中，file1 和 file2 都符合要求。换句话说，文件并不一样要求时确切的 766 权限。它将会显示任何属于（高于）此权限的文件 。
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然后，让我们使用 “/” 参数前置，看看会发生什么。
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```
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find -perm /222
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```
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![][6]
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上述命令将会查询所有者、用户组或其他拥有写权限的文件。这里有另外一个例子
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```
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find -perm /220
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```
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这条命令会查询所有者或用户组中拥有写权限的文件。这意味着 **所有者和用户组** 中匹配 **不全拥有写权限**。
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如果你使用 “-” 前缀运行相同的命令，你只会看到所有者和用户组都拥有写权限的文件。
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```
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find -perm -220
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```
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下面的截图会告诉你这两个参数前缀的不同。
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![][7]
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如我之前说过的一样，我们可以使用符号表示文件权限。
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请阅读：
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### 基于符号的文件权限查询文件
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在下面的例子中，我们使用例如 **u**（所有者），**g**（用户组） 和 **o**（其他） 的符号表示法。我们也可以使用字母 **a** 代表上述三种类型。我们可以通过特指的 **r** (读), **w** (写), **x** (执行) 分别代表它们的权限。
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例如，寻找用户组中拥有 **写** 权限的文件，执行：
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```
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find -perm -g=w
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```
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![][8]
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上面的例子中，file1 和 file2 都拥有 **写** 权限。请注意，你可以等效使用 “=”或“+”两种符号标识。例如，下列两行相同效果的代码。
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```
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find -perm -g=w
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find -perm -g+w
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```
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查询文件所有者中拥有写权限的文件，执行：
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```
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find -perm -u=w
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```
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查询所有用户中拥有写权限的文件，执行：
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```
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find -perm -a=w
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```
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查询 **所有者** 和 **用户组** 中同时拥有写权限的文件，执行：
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```
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find -perm -g+w,u+w
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```
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上述命令等效与“find -perm -220”。
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查询 **所有者** 或 **用户组** 中拥有写权限的文件，执行：
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```
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find -perm /u+w,g+w
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```
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或者,
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```
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find -perm /u=w,g=w
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```
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上述命令等效于 “find -perm /220”。
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更多详情，参照 man 手册。
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```
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man find
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```
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了解更多简化案例或其他 Linux 命令，查看[**man 手册**][9]。
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然后，这就是所有的内容。希望这个教程有用。更多干货，敬请关注。
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干杯！
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--------------------------------------------------------------------------------
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via: https://www.ostechnix.com/find-files-based-permissions/
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作者：[][a]
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译者：[CYLeft](https://github.com/CYLeft)
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||||
校对：[校对者ID](https://github.com/校对者ID)
|
||||
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||||
本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出
|
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|
||||
[a]:https://www.ostechnix.com
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[1]:https://www.ostechnix.com/find-sort-files-based-access-modification-date-time-linux/
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[2]:data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7/
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[3]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-1-1.png
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[4]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-2.png
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[5]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-3.png
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[6]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-6.png
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[7]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-7.png
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[8]:https://www.ostechnix.com/wp-content/uploads/2017/12/find-files-8.png
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[9]:https://www.ostechnix.com/3-good-alternatives-man-pages-every-linux-user-know/
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Loading…
Reference in New Issue
Block a user