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OpenSolaris 2009.06 - man page for umask (opensolaris section 1)

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umask(1)				  User Commands 				 umask(1)

NAME
       umask - get or set the file mode creation mask

SYNOPSIS
       /usr/bin/umask [-S] [mask]

   sh
       umask [ooo]

   csh
       umask [ooo]

   ksh
       umask [-S] [mask]

   ksh93
       umask [-S] [mask]

DESCRIPTION
       The umask utility sets the file mode creation mask of the current shell execution environ-
       ment to the value specified by the mask operand. This mask affects the  initial	value  of
       the  file  permission bits of subsequently created files. If umask is called in a subshell
       or separate utility execution environment, such as one of the following:

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

       it does not affect the file mode creation mask of the caller's environment. For this  rea-
       son,  the /usr/bin/umask utility cannot be used to change the umask in an ongoing session.
       Its usefulness is limited to checking the caller's umask. To change the umask of an  ongo-
       ing session you must use one of the shell builtins.

       If  the	mask operand is not specified, the umask utility writes the value of the invoking
       process's file mode creation mask to standard output.

   sh
       The user file-creation mode  mask  is  set  to  ooo.  The  three  octal	digits	refer  to
       read/write/execute  permissions	for  owner, group, and other, respectively (see chmod(1),
       chmod(2), and umask(2)). The value of each specified digit is subtracted from  the  corre-
       sponding  ``digit'' specified by the system for the creation of a file (see creat(2)). For
       example, umask 022 removes write permission for group and other. Files  (and  directories)
       normally  created with mode 777 become mode 755. Files (and directories) created with mode
       666 become mode 644).

	   o	  If ooo is omitted, the current value of the mask is printed.

	   o	  umask is recognized and executed by the shell.

	   o	  umask can be included in the user's .profile (see profile(4))  and  invoked  at
		  login  to automatically set the user's permissions on files or directories cre-
		  ated.

   csh
       See the description above for the Bourne shell (sh)umask built-in.

   ksh
       The user file-creation mask is set to mask. mask can either be an octal number or  a  sym-
       bolic value as described in chmod(1). If a symbolic value is given, the new umask value is
       the complement of the result of applying mask to the  complement  of  the  previous  umask
       value. If mask is omitted, the current value of the mask is printed.

   ksh93
       umask  sets the file creation mask of the current shell execution environment to the value
       specified by the mask operand. This mask affects the file permission bits of  subsequently
       created	files.	mask  can  either  be an octal number or a symbolic value as described in
       chmod(1). If a symbolic value is specified, the new file creation mask is  the  complement
       of  the	result	of  applying mask to the complement of the current file creation mask. If
       mask is not specified, umask writes the value of the file creation mask	for  the  current
       process to standard output.

OPTIONS
   ksh
       The following option is supported for /usr/bin/umask and umask in ksh:

       -S    Produces symbolic output.

       The default output style is unspecified, but will be recognized on a subsequent invocation
       of umask on the same system as a mask operand to restore the previous file  mode  creation
       mask.

   ksh93
       The following option is supported in ksh93:

       -S    Causes  the  file	creation mask to be written or treated as a symbolic value rather
	     than an octal number.

OPERANDS
       The following operand is supported:

       mask    A string specifying the new file mode creation mask. The string is treated in  the
	       same way as the mode operand described in the chmod(1) manual page.

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

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

	       The interpretation of mode values that specify file mode bits other than the  file
	       permission bits is unspecified.

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

	       The default output of a prior invocation of umask on the same system with no oper-
	       and will also be recognized as a mask operand. The use of an operand  obtained  in
	       this way is not obsolescent, even if it is an octal number.

OUTPUT
       When the mask operand is not specified, the umask utility will write a message to standard
       output that can later be used as a umask mask operand.

       If -S is specified, the message will be in the following format:

	 "u=%s,g=%s,o=%s\n", owner permissions, group permissions, \
				 other permissions

       where the three values will be combinations of letters from the set {r, w, x}.  The  pres-
       ence  of  a letter will indicate that the corresponding bit is clear in the file mode cre-
       ation mask.

       If a mask operand is specified, there will be no output written to standard output.

EXAMPLES
       Example 1 Using the umask Command

       The examples in this section refer  to  the  /usr/bin/umask  utility  and  the  ksh  umask
       builtin.

       Either of the commands:

	 umask a=rx,ug+w
	 umask 002

       sets the mode mask so that subsequently created files have their S_IWOTH bit cleared.

       After  setting  the  mode mask with either of the above commands, the umask command can be
       used to write the current value of the mode mask:

	 example$ umask
	 0002

       The output format is unspecified, but historical implementations use the obsolescent octal
       integer mode format.

	 example$ umask -S
	 u=rwx,g=rwx,o=rx

       Either  of these outputs can be used as the mask operand to a subsequent invocation of the
       umask utility.

       Assuming the mode mask is set as above, the command:

	 umask g-w

       sets the mode mask so that subsequently created files have their S_IWGRP and S_IWOTH  bits
       cleared.

       The command:

	 umask --w

       sets  the  mode mask so that subsequently created files have all their write bits cleared.
       Notice that mask operands r, w, x, or anything beginning with a hyphen (-), must  be  pre-
       ceded by - to keep it from being interpreted as an option.

ENVIRONMENT VARIABLES
       See  environ(5)	for  descriptions  of the following environment variables that affect the
       execution of umask: LANG, LC_ALL, LC_COLLATELC_CTYPE, LC_MESSAGES, and NLSPATH.

EXIT STATUS
       The following exit values are returned:

       0     The file mode creation mask was successfully changed, or no mask  operand	was  sup-
	     plied.

       >0    An error occurred.

ATTRIBUTES
       See attributes(5) for descriptions of the following attributes:

   /usr/bin/umask, csh, ksh, sh
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+

   ksh93
       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |External			   |
       +-----------------------------+-----------------------------+

SEE ALSO
       chmod(1),  csh(1),  ksh(1),  ksh93(1),  sh(1),  chmod(2),  creat(2), umask(2), profile(4),
       attributes(5), environ(5), standards(5)

SunOS 5.11				   17 Sep 2007					 umask(1)
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