NAME
ulimit - set or report file size limit
SYNOPSIS
ulimit [-f][blocks]
DESCRIPTION
The ulimit utility shall set or report the file-size writing limit
imposed on files written by the shell and its child processes (files of
any size may be read). Only a process with appropriate privileges can
increase the limit.
OPTIONS
The ulimit utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following option shall be supported:
-f Set (or report, if no blocks operand is present), the file size
limit in blocks. The -f option shall also be the default case.
OPERANDS
The following operand shall be supported:
blocks The number of 512-byte blocks to use as the new file size limit.
STDIN
Not used.
INPUT FILES
None.
ENVIRONMENT VARIABLES
The following environment variables shall affect the execution of
ulimit:
LANG Provide a default value for the internationalization variables
that are unset or null. (See the Base Definitions volume of
IEEE Std 1003.1-2001, Section 8.2, Internationalization
Variables for the precedence of internationalization variables
used to determine the values of locale categories.)
LC_ALL If set to a non-empty string value, override the values of all
the other internationalization variables.
LC_CTYPE
Determine the locale for the interpretation of sequences of
bytes of text data as characters (for example, single-byte as
opposed to multi-byte characters in arguments).
LC_MESSAGES
Determine the locale that should be used to affect the format
and contents of diagnostic messages written to standard error.
NLSPATH
Determine the location of message catalogs for the processing of
LC_MESSAGES .
ASYNCHRONOUS EVENTS
Default.
STDOUT
The standard output shall be used when no blocks operand is present. If
the current number of blocks is limited, the number of blocks in the
current limit shall be written in the following format:
"%d\n", <number of 512-byte blocks>
If there is no current limit on the number of blocks, in the POSIX
locale the following format shall be used:
"unlimited\n"
STDERR
The standard error shall be used only for diagnostic messages.
OUTPUT FILES
None.
EXTENDED DESCRIPTION
None.
EXIT STATUS
The following exit values shall be returned:
0 Successful completion.
>0 A request for a higher limit was rejected or an error occurred.
CONSEQUENCES OF ERRORS
Default.
The following sections are informative.
APPLICATION USAGE
Since ulimit affects the current shell execution environment, it is
always provided as a shell regular built-in. If it is called in a
separate utility execution environment, such as one of the following:
nohup ulimit -f 10000
env ulimit 10000
it does not affect the file size limit of the caller’s environment.
Once a limit has been decreased by a process, it cannot be increased
(unless appropriate privileges are involved), even back to the original
system limit.
EXAMPLES
Set the file size limit to 51200 bytes:
ulimit -f 100
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
The System Interfaces volume of IEEE Std 1003.1-2001, ulimit()
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- 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 .