UMASK(2) BSD System Calls Manual UMASK(2)NAME
umask -- set file creation mode mask
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
mode_t
umask(mode_t numask);
DESCRIPTION
The umask() routine sets the process's file mode creation mask to numask and returns the previous value of the mask. The 9 low-order access
permission bits of numask are used by system calls, including open(2), mkdir(2), mkfifo(2) and mknod(2) to turn off corresponding bits
requested in file mode. (See chmod(2)). This clearing allows each user to restrict the default access to his files.
The default mask value is S_IWGRP|S_IWOTH (022, write access for the owner only). Child processes inherit the mask of the calling process.
RETURN VALUES
The previous value of the file mode mask is returned by the call.
ERRORS
The umask() function is always successful.
SEE ALSO chmod(2), mkdir(2), mkfifo(2), mknod(2), open(2)STANDARDS
The umask() function call is expected to conform to IEEE Std 1003.1-1988 (``POSIX.1'').
4th Berkeley Distribution June 4, 1993 4th Berkeley Distribution
Check Out this Related Man Page
UMASK(2) Linux Programmer's Manual UMASK(2)NAME
umask - set file mode creation mask
SYNOPSIS
#include <sys/types.h>
#include <sys/stat.h>
mode_t umask(mode_t mask);
DESCRIPTION
umask() sets the calling process's file mode creation mask (umask) to mask & 0777 (i.e., only the file permission bits of mask are used),
and returns the previous value of the mask.
The umask is used by open(2), mkdir(2), and other system calls that create files to modify the permissions placed on newly created files or
directories. Specifically, permissions in the umask are turned off from the mode argument to open(2) and mkdir(2).
The constants that should be used to specify mask are described under stat(2).
The typical default value for the process umask is S_IWGRP | S_IWOTH (octal 022). In the usual case where the mode argument to open(2) is
specified as:
S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH | S_IWOTH
(octal 0666) when creating a new file, the permissions on the resulting file will be:
S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH
(because 0666 & ~022 = 0644; i.e., rw-r--r--).
RETURN VALUE
This system call always succeeds and the previous value of the mask is returned.
CONFORMING TO
SVr4, 4.3BSD, POSIX.1-2001.
NOTES
A child process created via fork(2) inherits its parent's umask. The umask is left unchanged by execve(2).
The umask setting also affects the permissions assigned to POSIX IPC objects (mq_open(3), sem_open(3), shm_open(3)), FIFOs (mkfifo(3)), and
Unix domain sockets (unix(7)) created by the process. The umask does not affect the permissions assigned to System V IPC objects created
by the process (using msgget(2), semget(2), shmget(2)).
SEE ALSO chmod(2), mkdir(2), open(2), stat(2)COLOPHON
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.
Linux 2008-01-09 UMASK(2)
Working out of AIX 4.3's .
have machine (a) and machine (b)
umask on both machines is 'umask 022'.
as user root (these are trivial machines hence dummies like me have root access) when i Ftp files from a to b , why is it that I loose the original file permissions. After the ftp I have to chmod... (1 Reply)
Hi,
I need to change my umask from 22 to 0022. FreeBSD 5.4 has different way of looking at 22 and 0022. Untill 4.11 stable 022 and 0022 were same. Can anyone help me?
Thanks in advance.
Jimmy (0 Replies)
Hi,
Do you know if it's possible to have the user list with their umask on AIX system ?
I need to check if they are OK but with smit and user by user, it will take all the day. :)
An idea ?
Thx a lot. (3 Replies)
Hi,
We have umask 022 in /etc/profile for security reasons.
But I want have some other umask for selected users. how to achieve this?
Regards (3 Replies)
Hi All,
I am trying to ftp a file :
-rw-rw-rw- 1 oraclepbdw dba filename.txt
from Machine A ( where umask is 022) to Machine B (umask 022)
but the file changes to
-rw-rw-r-- 1 ftpamle3 ftaml filename.txt
Dur some constraints the group of the users on either side... (3 Replies)
Hi,
I have a doubt on the umask values.
Why is the UMASK value is different from file and directory?
Suppose if the umask value is 0022. The file permissions for a newly created file is 644 and the file permissions for a newly created directory is 755.
My doubt is why can't it be the... (1 Reply)
How can we set the Sticky bit in the umask itself. Please help me :confused:
I tried to set like umask 1000 but when I run umask, the value of umask is 00 (0 Replies)
Hi,
I got this redhat ent 4 assigned to me now.
/etc/bashrc
if ; then
umask 022
else
umask 077
fi
What does it mean?
I created already three user and it never had 022 umask, always 077.
Thank you in advance. (3 Replies)
Hi all,
The configuration:
We are useing a HP-UX Server with vxfs File System. The files on this server have normally a umask of 022 (owned by a administrative account) users who have write access to certain files get custom ACL entries that add these rights for the specific user.
Now a... (0 Replies)
Hi All,
i was reading up on a umask question on this forum and have a question on this.
the umask value on my home PC running on cygwin is 022. when i create a dir it defaults to permission 755, when i create a file it defaults to 644. Now it starts at 777 for dirs and 666 for files and... (1 Reply)