umask(1)						      General Commands Manual							  umask(1)

NAME

       umask - set or display the file mode creation mask

SYNOPSIS

   Set Mask
   Display Mask
DESCRIPTION

       The command sets the value of the file mode creation mask or displays the current one.  The mask affects the initial value of the file mode
       (permission) bits for subsequently created files.

   Setting the File Mode Creation Mask
       The command sets a new file mode creation mask for the current shell execution environment.  mask can be a symbolic  or	numeric  (obsoles-
       cent) value.

       A symbolic mask provides a flexible way of modifying the mask permission bits individually or as a group.  A numeric mask specifies all the
       permission bits at one time.

       When a mask is specified, no output is written to standard output.  A symbolic mask replaces or modifies the  current  file  mode  creation
       mask.  It is specified as a comma-separated list of operations in the following format.	Whitespace is not permitted.

	      [who][operator][permissions][, ...]

       The fields can have the following values:

	      who	     One or more of the following letters:

				  Modify permissions for user (owner).
				  Modify permissions for group.
				  Modify permissions for others.

			     Or:

				  Modify permissions for all
					 =

	      operator	     One of the following symbols:

				  Add	 permissions to the existing mask for who.
				  Delete permissions from the existing mask for who.
				  Replace the existing mask for
					 who with permissions.

	      permissions    One or more of the following letters:

				  The read permission.

				  The write permission.

				  The execute/search permission.

       If one or two of the fields are omitted, the following table applies:
												 |
					Format Entered	      Effect				 | Input   Equals
					---------------------------------------------------------+----------------
					who		      Delete current permissions for who |
					operator	      No action 			 |	   (none)
					permissions	      Equal to: 			 |
							      Delete current permissions for who |
							      No action 			 |	   (none)
							      No action 			 |	   (none)
					whopermissions	      Equal to: 			 |

					operatorpermissions   Equal to: 			 |
       A numeric mask replaces the current file mode creation mask.  It is specified as an unsigned octal integer, constructed from the logical OR
       (sum) of the following mode bits (leading zeros can be omitted):

   Displaying the Current Mask Value
       To display the current file mode creation mask value, use one of the commands:

	      Print the current file mode creation mask in a symbolic format:

			     The characters (read), (write), and (execute/search) represent the bits that are clear in the mask for  (user/owner),
			     (group), and (other).  All other bits are set.

	      Print the current file mode creation mask as an octal value.

			     The  zero bits in the numeric value correspond to the displayed and permission characters in the symbolic value.  The
			     one bits in the numeric value correspond to the missing permission characters in the symbolic value.

			     Depending on implementation, the display consists of one to four octal digits; the first digit is	always	zero  (see
			     DEPENDENCIES).  The rightmost three digits (leading zeros implied as needed) represent the bits that are set or clear
			     in the mask.

       Both forms produce output that can be used as the mask argument to set the mask in a subsequent command.

   General Operation
       When a new file is created (see creat(2)), each bit that is set in the file mode creation mask causes the corresponding permission  bit	in
       the  the  file  mode  to  be  cleared (disabled).  Conversely, bits that are clear in the mask allow the corresponding file mode bits to be
       enabled in newly created files.

       For example, the mask (octal disables group and other write permissions.  As a result, files normally created with a file mode shown by the
       command as (octal become mode (octal while files created with file mode (octal become mode (octal

       Note that the file creation mode mask does not affect the set-user-id, set-group-id, or "sticky" bits.

       The file creation mode mask is also used by the command (see chmod(1)).

       Since affects the current shell execution environment, it is generally provided as a shell regular built-in (see DEPENDENCIES).

       If is called in a subshell or separate utility execution environment, such as one of the following:

       it does not affect the file mode creation mask of the calling environment.

       The default mask is (octal

RETURN VALUE

       exits with one of the following values:

	      The file mode creation mask was successfully changed
		     or no mask operand was supplied.
	      An error occurred.

EXAMPLES

       In these examples, each line show an alternate way of accomplishing the same task.

       Set  the  value	to  produce  read and write permissions for the file's owner and read permissions for all others displays on newly created
       files):

       Set the value to produce read, and write permissions for the file's owner, read-only for others users in the same group, and no	access	to
       others

       Set the value to deny read, write, and execute permissions to everyone

       Add the write permission to the current mask for everyone (there is no equivalent numeric mode):

WARNINGS

       If you set a mask that prevents read or write access for the user (owner), many programs, such as editors, that create temporary files will
       fail because they cannot access the file data.

DEPENDENCIES

       The command is implemented both as a separate executable file and as built-in shell commands.

   POSIX Shell and Separate File
       All features are supported (see sh-posix(1)).  The numeric mask display uses a minimum of two digits.

   Korn Shell
       The option is not supported in the Korn shell built-in command (see ksh(1)).  The numeric mask display uses a minimum of two digits.

   C Shell
       The option and symbolic mask values are not supported in the C shell built-in command (see csh(1)).  The numeric mask display uses a  mini-
       mum of one digit.

SEE ALSO

       chmod(1), csh(1), ksh(1), sh-posix(1), sh(1), chmod(2), creat(2), umask(2).

STANDARDS CONFORMANCE

																	  umask(1)