File Permissions

File permissions in PHP control who can read, write, and execute a file. They're crucial for the security and proper functioning of your PHP applications. When working with files, you can use functions like chmod(), is_readable(), and is_writable() to manage permissions. Typically, you would use chmod() to change the permissions of a file. The first parameter is the name of the file and the second parameter is the mode. For instance, chmod($file, 0755) would assign owner permissions to read, write, and execute, while everyone else would only have read and execute permissions. To know if a file is readable or writable, use is_readable() or is_writable() respectively.