solaris - 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 ]
DESCRIPTION
/usr/bin/umask
The umask utility sets the file mode creation mask of the
current shell execution environment 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.
If the mask operand is not specified, the umask utility
writes the value of the invoking process's file mode crea-
tion 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 corresponding ``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 normally created with mode 777 become mode 755;
files created with mode 666 become mode 644).
If ooo is omitted, the current value of the mask is
printed.
umask is recognized and executed by the shell.
umask can be included in the user's .profile (see pro-
file(4) ) and invoked at login to automatically set the
user's permissions on files or directories created.
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 symbolic 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 com-
plement of the previous umask value. If mask is omitted,
the current value of the mask is printed.
OPTIONS
The following option is supported:
-S Produce symbolic output.
The default output style is unspecified, but will be recog-
nised on a subsequent invocation of umask on the same system
as a mask operand to restore the previous file mode creation
mask.
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 speci-
fied by the symbolic_mode string.
In a symbolic_mode value, the permissions op charac-
ters + and - are interpreted relative to the current
file mode creation mask; + causes the of for the
indicated 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 operand will also be recog-
nized 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 permis-
sions>, <other permissions>
where the three values will be combinations of letters from
the set {r, w, x}; the presence of a letter will indicate
that the corresponding bit is clear in the file mode crea-
tion mask.
If a mask operand is specified, there will be no output
written to standard output.
EXAMPLES
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 com-
mands, the umask command can be used to write the current
value of the mode mask:
$ umask
0002
(The output format is unspecified, but historical implemen-
tations use the obsolescent octal integer mode format.)
$ umask -S 1
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. Note that mask operands r , w
, x or anything beginning with a hyphen, must be preceded by
-- to keep it from being interpreted as an option.
See environ(5) for descriptions of the following environment
variables that affect the execution of umask: LC_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
>0 An error occurred.
SEE ALSO
chmod(1), csh(1), ksh(1), sh(1), chmod(2), creat(2), pro-
file(4), environ(5)