umask(1)						      General Commands Manual							  umask(1)

NAME

       umask - Displays or sets the file mode creation mask

SYNOPSIS

       umask [-S] [mask]

									  Note

       The  C shell  has a built-in version of the umask command.  If you are using the C shell, and want to guarantee that you are using the com-
       mand described here, you must specify the full path /usr/bin/umask.  See the csh(1) reference page for a description of the  built-in  com-
       mand.

STANDARDS

       Interfaces documented on this reference page conform to industry standards as follows:

       umask:  XCU5.0

       Refer to the standards(5) reference page for more information about industry standards and associated tags.

OPTIONS

       Produce symbolic output.

	      Output is produced in a format that is recognized on a subsequent invocation of umask as a mask operand to restore the previous file
	      mode creation mask.

       If the -S option is not used, output is displayed as an octal integer, but is still usable as input on a subsequent invocation of the umask
       command.

OPERANDS

       A string specifying the new file mode creation mask. This string may may be an octal value or a symbolic_mode value.

	      For  a  symbolic_mode value, the new value of the file mode creation mask is the logical complement of the file permission bits por-
	      tion of the file mode specified by the symbolic_mode string.

	      In a symbolic_mode value, the characters + and - are interpreted relative to the current file mode creation mask; + causes the  bits
	      for the indicated permissions to be cleared in the mask; - causes the bits for the indicated permissions to be set in the mask.

	      The file mode creation mask is set to the resulting numeric value.

	      In the obsolescent octal integer form of mode, the specified bits are set in the file mode creation mask.

DESCRIPTION

       The  umask  command sets the  file mode	creation mask of the current shell execution environment to the value specified  by the mask oper-
       and. This mask affects the initial value of the file permission bits of subsequently created files.

       If the mask operand is not specified, the umask command writes the value of the invoking process's file mode creation mask to standard out-
       put.

       If the -S option is specified, the output is in the following format:

       "u=%s,g=%s,o=%s
", <owner permissions>, <group permissions>, <other permissions>"

       The three values are combinations of letters from the set {r, w, x}; the presence of a letter indicates that the corresponding bit is clear
       in the file mode creation mask.

NOTES

       Any mask operand such as -r, -w, -x, or anything beginning with a hyphen, must be preceded by -- to keep it from  being	interpreted  as  a
       option.	Since umask affects the current shell execution environment, it is provided as a shell regular built-in.  In contrast to the nega-
       tive permission logic provided by the file mode creation mask and the octal number form of the mask argument, the symbolic form of the mask
       operand specifies those permissions that are left alone.  Although the references to octal modes are obsolescent in the ISO/IEC 9945-2:1993
       standard, they are maintained for portable applications until further notice.

RESTRICTIONS

       If umask is called in a subshell or separate utility execution environment, it does not affect the file mode creation mask of the  caller's
       environment.  A separate execution environment could be one of the following:

       (umask 002) nohup umask ...  find . -exec umask ... ;

EXIT STATUS

       The  following  exit  values are returned: The file mode creation mask was successfully changed, or no mask operand was supplied.  An error
       occurred.

EXAMPLES

       To set the file mode creation mask so that subsequently created files have their write by all others bit cleared, enter either of the  fol-
       lowing  commands: umask a=rx,ug+w umask 002 If the file mode creation mask was set with either of the above commands, the umask command can
       be used to write out the current value of the mask.  To write the value in octal format, enter: umask

	      This provides the output: 0002

	      To write the value in symbolic format, enter: umask -S

	      This provides the output: u=rwx,g=rwx,o=rx The following sequence of commands is an example of how to save  the  current	file  mode
	      creation mask and later restore the value using the umask command and octal integer formats.  Examine the current value of the mask:
	      umask

	      The current mask is reported as: 022 Save the current value, and verify the saved value: SAVEMASK  =`umask` echo $SAVEMASK

	      The saved value is reported as: 022 Change the current mask: umask 444 Verify the change: umask  The  new  mask  is  reported:  0444
	      Restore the previous mask: umask $SAVEMASK Verify the restored value: umask

	      The value is now restored: 022

	      The  following  sequence	of  commands  is an example of how to save the current file mode creation mask and later restore the value
	      using the umask command and symbolic_mode formats.  Examine the current value of the mask: umask -S

	      The current mask is reported as: u=rwx,g=rx,o=rx Save the current value, and verify the saved value: SAVEMASK=`umask -S` echo $SAVE-
	      MASK

	      The  saved  value  is  reported  as:  u=rwx,g=rx,o=rx  Change the current mask: umask a= Verify the change: umask -S The new mask is
	      reported: u=,g=,o= Restore the previous mask: umask $SAVEMASK Verify the restored value: umask -S

	      The value is now restored: u=rwx,g=rx,o=rx

	      To set the file mode creation mask so that subsequently created files have all their write bits cleared, enter: umask -- -w

ENVIRONMENT VARIABLES

       The following environment variables affect the execution of umask: Provides a default value for the internationalization variables that are
       unset or null. If LANG is unset or null, the corresponding value from the default locale is used.  If any of the internationalization vari-
       ables contain an invalid setting, the utility behaves as if none of the variables had been defined.  If set to a  non-empty  string  value,
       overrides  the  values of all the other internationalization variables.	Determines the locale for the interpretation of sequences of bytes
       of text data as characters (for example, single-byte as opposed to multibyte characters in arguments).  Determines the locale for the  for-
       mat  and  contents  of  diagnostic messages written to standard error.  Determines the location of message catalogues for the processing of
       LC_MESSAGES.

SEE ALSO

       Commands:  chmod(1)

       Functions:  chmod(2), umask(2)

       Standards:  standards(5)

																	  umask(1)