umask - macOS


umask is a macOS command used to set or display the file mode creation mask. It allows you to specify the default permissions for newly created files and directories.


umask [-S] [-s] [-u] [mask]


  • -S, –symbolic: Symbolically display the file mode creation mask.
  • -s, –status: Display the current file mode creation mask.
  • -u, –unset: Revoke file mode creation mask permissions.
  • mask: An octal number representing the file mode creation mask.


Display Current Mask

umask -s

Set Mask Symbolically

umask -S u+w,go-wx

Set Mask Octal

umask 0046    # Set user read and write, group and other read

Common Issues

  • Incorrect mask format: The mask argument must be a valid octal number (0-7).
  • Invalid permissions: Ensure that the permissions specified in the mask are valid (e.g., user write permission cannot be revoked for user-owned files).


umask can be used in conjunction with other commands to control file permissions. For example:

touch file
umask 022
chmod -R g+w file

This command creates a file with default permissions, then changes the mask to restrict group write permissions, and finally grants group write permissions recursively to the file.

  • chmod: Change file permissions.
  • chown: Change file ownership and group.
  • stat: Display file attributes, including permissions.