PHP Tutorial - PHP umask() Function


The umask() function changes the file permissions for files.

This function sets PHP's umask to mask & 0777 and returns the old umask.

Calling umask() without any arguments returns the current umask.


PHP umask() Function has the following syntax.



ParameterIs requiredDescription
maskOptional.New permissions. Default is 0777

The mode parameter consists of four numbers:

  • The first number is always zero
  • The second number specifies permissions for the owner
  • The third number specifies permissions for the owner's user group
  • The fourth number specifies permissions for everybody else

Possible values (to set multiple permissions, add up the following numbers):

  • 1 = execute permissions
  • 2 = write permissions
  • 4 = read permissions


umask() without arguments simply returns the current umask otherwise the old umask is returned.


<?php//from   ww  w . j a  v  a  2 s. c  o m
$old = umask(0);
chmod("test.txt", 0755);

// Checking
if ($old != umask()) {
    die('An error occurred while changing back the umask');