Let's talk about various functions of deleting files in PHP

In PHP, we need to manage or operate files from time to time. In some cases we need to delete files. PHP provides many functions to delete files, allowing users to delete files easily. In this article, we will explore various functions in PHP to delete files.

1. unlink() function

The unlink() function is used to delete files. Simply put, the unlink() function deletes a file by file name. If the deletion is successful, it returns TRUE. If the deletion fails, it returns FALSE. The following is the basic usage of using the unlink() function to delete files:

$filename = "example.txt";
if (unlink($filename)) {
    echo "File deleted successfully";
} else {
    echo "File could not be deleted";
}

The above code deletes the example.txt file and prints out the corresponding results. If the file does not exist, it will prompt that the file does not exist.

2. rmdir() function

When we need to delete a directory, we need to use the rmdir() function. Simply put, the rmdir() function deletes a directory by its name. If the deletion is successful, TRUE is returned, otherwise FALSE is returned. The following is the basic usage of using the rmdir() function to delete a directory:

$dirname = "example";
  if (rmdir($dirname)) {
      echo "Directory deleted successfully";
  } else {
      echo "Directory could not be deleted";
  }

The above code deletes the example directory and prints out the corresponding results. If the directory does not exist, it will prompt that the directory does not exist.

3. unlink() vs rmdir()

Although the unlink() and rmdir() functions are both used to delete files and directories, there are still differences between them.

unlink() can only delete files, and the rmdir() function can only delete directories. Therefore, you cannot pass a directory as a parameter to the unlink() function.

The unlink() function will not delete the directory, but will only delete the specified file.

The rmdir() function can successfully delete the directory only when the directory is empty, otherwise all files and subdirectories of the directory will be deleted.

4. is_writeable() function

Before deleting the file, we need to determine whether the current PHP environment can delete the file. The is_writeable() function can determine whether a file or directory is writable.

If the file or directory write permission has been prohibited, the is_writeable() function returns FALSE, otherwise it returns TRUE. The following is how to use the is_writeable() function:

if (is_writeable('example.txt')){
    echo "File is writeable";
} else {
    echo "File is not writeable";
}

The above code will print out whether the file is writable.

5. Practical Guide to unlink() and rmdir()

Before deleting files and directories, be sure to determine whether the PHP environment allows deletion. At the same time, please choose carefully when deleting files and directories. Here are the guidelines you should follow when using the unlink() and rmdir() functions:

Please make sure you are removing the correct files and directories.

Use the is_writeable() function to check whether the file can be deleted.

Before deleting files and directories, please back up your files to prevent accidental deletion.

Be careful when performing deletion operations!

When deleting files and directories, do not use absolute paths unless you need to.

6. Conclusion

PHP's file deletion function is very practical, allowing us to easily delete files and directories. The above are several commonly used methods to delete files in PHP. However, when deleting files and directories using PHP, you should be extra careful to avoid accidentally deleting the files you need.

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