drupal_chmod in core/includes/drupal.inc
Sets the permissions on a file or directory.
file_prepare_directory in core/includes/file.inc
Checks that the directory exists and is writable.
file_save_htaccess in core/includes/file.inc
Creates a .htaccess file in the given directory.
file_save_upload in core/includes/file.inc
Saves a file upload to a new location.
file_unmanaged_copy in core/includes/file.inc
Copies a file to a new location without database changes or hook invocation.
file_unmanaged_move in core/includes/file.inc
Moves a file to a new location without database changes or hook invocation. This is a powerful function that in many ways performs like an advanced version of rename().
image_save in core/includes/image.inc
Closes the image and saves the changes to a file.
system_check_directory in core/modules/system/system.module
Checks the existence of the directory specified in $form_element.
_color_save_stylesheet in core/modules/color/color.module
Saves the rewritten stylesheet to disk.