PHP uses the fopen function to open a file and prompts insufficient permissions.

PHP fopen() function

Function definition and usage: The fopen() function opens a file or URL.
Syntax:

fopen(filename, mode, include_path, context)

The last two parameters are optional. We only used the first two parameters. The code is as follows:

<code><span><span><?php </span><span>//打开文件流</span><span>$myfile</span> = fopen(<span>"newfile.txt"</span>, <span>"w"</span>)
        <span>or</span><span>die</span>(<span>"Unable to open file!"</span>);

<span>//向文件中写入字符串</span>
fwrite(<span>$myfile</span>, <span>"Hello World"</span>);

<span>//关闭文件句柄</span>
fclose(<span>$myfile</span>);
<span>?></span></span></span></code>

The functions implemented by the code are: The writing mode opens a file named newfile.txt in the current path. If the file does not exist, try to create it. After opening the file, write the Hello World string to the file, and finally close the file.

There is no newfile.txt file in the current folder path. When executing the above code, the following error occurs:

Warning: fopen(newfile.txt): failed to open stream: Insufficient permissions in
/home/yums/web/ blog_for_r&d/scripts/testOpen.php on line 3
Unable to open file!

Insufficient permissions? The most common problem under Linux is that you don’t have permission to create files on the hard disk? I tried to give testOpen.php higher permissions, so I executed the following command in the terminal:

<code><span>sudo</span> chmod <span>666</span> testOpen.php</code>

In this way, the PHP file has the permission to create files. I will try refreshing the page again, WTF, still That’s the problem!

Warning: fopen(newfile.txt): failed to open stream: Insufficient permissions in
/home/yums/web/blog_for_r&d/scripts/testOpen.php on line 3
Unable to open file!

Forget it, I don’t use this function to create files. I use gedit to create the newfile.txt file myself. So I executed the following command in the terminal:

<code>gedit newfile<span>.txt</span></code>

In this way, I created a file and refreshed it. However, the permissions were still not enough. I’d better check what permissions the newfile.txt file has. I executed the following command in the terminal. :

<code>ls -<span>all</span></code>

I found that the newfile.txt created with Notepad only has read permission and no write permission. Well, here is the problem. Increase the write permission for the newfile.txt file:

<code><span>sudo</span> chmod <span>666</span> newfile.txt</code>

Now refresh the page. No error is reported, and the corresponding string is written in the file.

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The above introduces the problem of insufficient permissions when opening a file using the fopen function in PHP, including the relevant content. I hope it will be helpful to friends who are interested in PHP tutorials.