When using mkdir to create a folder, I found that this function has two parameters. The second parameter specifies permissions for the newly created folder. But if you use mkdir('file address', 0777); directly, you will find that the permissions of the new folder are not 777, but usually 022. Because when mkdir sets permissions for a folder, it performs a bitwise AND with the umask (user default permission attribute) value of the user currently logged in to the operating system, and the resulting value is the final permission value. What is umask? Where do the default permissions for files we create come from? How to change this default permission? When we log in to the system and create a file, there is always a default permission. So where does this permission come from? This is what umask does. umask sets the default permissions for files created by users. It has the opposite effect of chmod. umask sets the permission "complement code", while chmod sets the file permission code. Generally set in /etc/profile, $HOME/.bash_profile or $HOME/.profile
1. Solution to the problem of PHP mkdir() without write permission
Introduction: This article mainly introduces the solution to the problem of PHP mkdir() without write permission, and details the umask. For explanations and solutions to the lack of write permissions after mkdir(), friends in need can refer to
2. php’s mkdir() function creates a safer permission setting for a folder Method
Introduction: This article mainly introduces the mkdir() function of php to create a folder which is safer The permission setting method. The situation encountered is that the system umask affects the specified permission parameter of mkdir and is smaller than expected. Using the chmod function does not have this problem. Friends who need it can refer to it
3. phison-up10 mass production tool v1.78.00 PHP writing text log implementation code
Introduction: phison-up10 mass production tool v1.78.00:phison-up10 Mass production tool v1.78.00 PHP writing text log implementation code: Copy the code as follows:** * Write file* @param string $file file path* @param string $str write content* @param char $mode write mode* / function writeFile($file,$str,$mode='w') { $oldmask = @umask(0); $fp = @fopen($file,$mod
4. php umask function tutorial_PHP tutorial
Introduction: php umask function tutorial. php umask function tutorial umask value (PHP 4, PHP 5) umask - changes the current umask description int umask ([international $mask]) umask () sets the PHP umask value to mask
5. Detailed explanation of PHP Built-in function mkdir()_PHP tutorial
Introduction: Detailed explanation of PHP built-in function mkdir(). The function mkdir has two parameters, directory path and access permissions. Example mkdir(/tmp/ test,0777) Then the permission code to be obtained is not necessarily the one set above. The umask of the current system will be the same as the set value
6. php umask function Tutorial
Introduction: php umask function tutorial. php umask function tutorial umask value (PHP 4, PHP 5) umask - changes the current umask description int umask ([int $mask]) umask () sets the PHP umask value to mask
7. Detailed explanation of PHP built-in function mkdir()
Introduction: Detailed explanation of PHP built-in function mkdir(). The function mkdir has two parameters, directory path and access permission. For example, mkdir(/tmp/test,0777). Then the permission code to be obtained is not necessarily the one set above. The umask of the current system will be the same as the set value
8. MySQL umask causes backup error
Introduction: However, the permissions of MySQL on the newly created database directory are 700; the permissions of the data table files are 660; this makes us confused. Does MySQL not rely on the values set by the system itself? refer to
9. Solution to the problem of PHP mkdir() without write permission_php example
Introduction: This article mainly introduces PHP mkdir ()The solution to the problem of no write permission, a detailed explanation of umask and the solution to the problem of no write permission after mkdir(), friends in need can refer to
10. php's mkdir() function creates a folder with a safer permission setting method_php example
Introduction: This article mainly introduces php's mkdir() function to create files A safer way to set permissions. The situation encountered is that the system umask affects the specified permission parameters of mkdir and is smaller than expected. Using the chmod function does not have this problem. Friends who need it can refer to it
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The above is the detailed content of 10 recommended articles about the php umask() function. For more information, please follow other related articles on the PHP Chinese website!

PHP type prompts to improve code quality and readability. 1) Scalar type tips: Since PHP7.0, basic data types are allowed to be specified in function parameters, such as int, float, etc. 2) Return type prompt: Ensure the consistency of the function return value type. 3) Union type prompt: Since PHP8.0, multiple types are allowed to be specified in function parameters or return values. 4) Nullable type prompt: Allows to include null values and handle functions that may return null values.

In PHP, use the clone keyword to create a copy of the object and customize the cloning behavior through the \_\_clone magic method. 1. Use the clone keyword to make a shallow copy, cloning the object's properties but not the object's properties. 2. The \_\_clone method can deeply copy nested objects to avoid shallow copying problems. 3. Pay attention to avoid circular references and performance problems in cloning, and optimize cloning operations to improve efficiency.

PHP is suitable for web development and content management systems, and Python is suitable for data science, machine learning and automation scripts. 1.PHP performs well in building fast and scalable websites and applications and is commonly used in CMS such as WordPress. 2. Python has performed outstandingly in the fields of data science and machine learning, with rich libraries such as NumPy and TensorFlow.

Key players in HTTP cache headers include Cache-Control, ETag, and Last-Modified. 1.Cache-Control is used to control caching policies. Example: Cache-Control:max-age=3600,public. 2. ETag verifies resource changes through unique identifiers, example: ETag: "686897696a7c876b7e". 3.Last-Modified indicates the resource's last modification time, example: Last-Modified:Wed,21Oct201507:28:00GMT.

In PHP, password_hash and password_verify functions should be used to implement secure password hashing, and MD5 or SHA1 should not be used. 1) password_hash generates a hash containing salt values to enhance security. 2) Password_verify verify password and ensure security by comparing hash values. 3) MD5 and SHA1 are vulnerable and lack salt values, and are not suitable for modern password security.

PHP is a server-side scripting language used for dynamic web development and server-side applications. 1.PHP is an interpreted language that does not require compilation and is suitable for rapid development. 2. PHP code is embedded in HTML, making it easy to develop web pages. 3. PHP processes server-side logic, generates HTML output, and supports user interaction and data processing. 4. PHP can interact with the database, process form submission, and execute server-side tasks.

PHP has shaped the network over the past few decades and will continue to play an important role in web development. 1) PHP originated in 1994 and has become the first choice for developers due to its ease of use and seamless integration with MySQL. 2) Its core functions include generating dynamic content and integrating with the database, allowing the website to be updated in real time and displayed in personalized manner. 3) The wide application and ecosystem of PHP have driven its long-term impact, but it also faces version updates and security challenges. 4) Performance improvements in recent years, such as the release of PHP7, enable it to compete with modern languages. 5) In the future, PHP needs to deal with new challenges such as containerization and microservices, but its flexibility and active community make it adaptable.

The core benefits of PHP include ease of learning, strong web development support, rich libraries and frameworks, high performance and scalability, cross-platform compatibility, and cost-effectiveness. 1) Easy to learn and use, suitable for beginners; 2) Good integration with web servers and supports multiple databases; 3) Have powerful frameworks such as Laravel; 4) High performance can be achieved through optimization; 5) Support multiple operating systems; 6) Open source to reduce development costs.


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