I have created symbolic links to several frequently used commands, for example:
"lt" is a link to "ls -ltrgo|tail". What can I do to make these links available system-wide, or at least in the directories my coworkers are in most of the time? I have copied the link to several directories, and... (6 Replies)
Hi, I have a task to search for a file called 'Xstartup' in the whole system because there might be different versions of it which overrite eachother.
Can anyone suggest a smart command to run this search ? The machine needs to scan every single folder beginning from root.
Please help, I am... (5 Replies)
Hello,
I am new to shell scripting and I was trying to write a script that would force a system wide password change except for admins. I am having some trouble and any help that someone could give me would be greatly appreciated. I am trying to do it by using the UID as the marker for anyone... (6 Replies)
Hi all,
Is there any system wide limit on number of user threads. I only find nkthread as a tunable parameter,apart from the `per process limit`. (1 Reply)
Hi,
I need to look for a config file (ldap.conf) and pick the latest modified file.
`locate` tells me there are many ldap.conf's, some in /etc, /usr, /home, etc.
Is there some way I can sort them by last modified time via bash?
I was thinking maybe I could pipe the output of `locate` to `ls... (4 Replies)
Dear Fellows;
As being new to linux, i have tried to synamically load a custom library which overrides some system calls like conncet(), socket() etc.... for custom purposes.
It works well, if declaring the environment path LD_PRELOAD and execution of the application to be override... (0 Replies)
We need to have many of our users all send encrypted files to a single FTP server. The problem, if I understand how encryption/decryption works (which I don't), is that each user would normally have their own private and public key. The other end needs to be able to decrypt the file(s) using a... (6 Replies)
When looking for wherever a program or a filename appears in the system, a short scrip is "findinner" which another script calls with a long parameter list consisting of path names ending with ".sh" or ".menu". "findinner" looks like this:
# If not .savenn file, show name and result of grep.
#... (4 Replies)
I have downloaded and installed a library called htslib for specific bioinformatic use but not for the system (I'm using Ubuntu 18.04). Only parts of the library is needed for my exercise to parse data in a type called VCF format (basically tab-delimited file but contains many information in... (14 Replies)
Discussion started by: yifangt
14 Replies
LEARN ABOUT LINUX
umask
UMASK(P) POSIX Programmer's Manual UMASK(P)
NAME
umask - set and get the file mode creation mask
SYNOPSIS
#include <sys/stat.h>
mode_t umask(mode_t cmask);
DESCRIPTION
The umask() function shall set the process' file mode creation mask to cmask and return the previous value of the mask. Only the file per-
mission bits of cmask (see <sys/stat.h>) are used; the meaning of the other bits is implementation-defined.
The process' file mode creation mask is used during open(), creat(), mkdir(), and mkfifo() to turn off permission bits in the mode argument
supplied. Bit positions that are set in cmask are cleared in the mode of the created file.
RETURN VALUE
The file permission bits in the value returned by umask() shall be the previous value of the file mode creation mask. The state of any
other bits in that value is unspecified, except that a subsequent call to umask() with the returned value as cmask shall leave the state of
the mask the same as its state before the first call, including any unspecified use of those bits.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
Unsigned argument and return types for umask() were proposed. The return type and the argument were both changed to mode_t.
Historical implementations have made use of additional bits in cmask for their implementation-defined purposes. The addition of the text
that the meaning of other bits of the field is implementation-defined permits these implementations to conform to this volume of
IEEE Std 1003.1-2001.
FUTURE DIRECTIONS
None.
SEE ALSO
creat() , mkdir() , mkfifo() , open() , the Base Definitions volume of IEEE Std 1003.1-2001, <sys/stat.h>, <sys/types.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE
and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained
online at http://www.opengroup.org/unix/online.html .
IEEE /The Open Group 2003 UMASK(P)