ULIMIT(1P) POSIX Programmer's Manual ULIMIT(1P)PROLOG
This manual page is part of the POSIX Programmer's Manual. The Linux
implementation of this interface may differ (consult the corresponding
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NAMEulimit — set or report file size limit
SYNOPSISulimit [−f] [blocks]
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.
The ulimit utility shall conform to the Base Definitions volume of
POSIX.1‐2008, 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
The following operand shall be supported:
blocks The number of 512-byte blocks to use as the new file size
The following environment variables shall affect the execution of
LANG Provide a default value for the internationalization vari‐
ables that are unset or null. (See the Base Definitions vol‐
ume of POSIX.1‐2008, Section 8.2, Internationalization Vari‐
ables 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).
Determine the locale that should be used to affect the format
and contents of diagnostic messages written to standard
NLSPATH Determine the location of message catalogs for the processing
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:
The standard error shall be used only for diagnostic messages.
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
The following sections are informative.
Since ulimit affects the current shell execution environment, it is
always provided as a shell regular built-in. If it is called in a sepa‐
rate 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
Set the file size limit to 51200 bytes:
ulimit −f 100
The Base Definitions volume of POSIX.1‐2008, Chapter 8, Environment
Variables, Section 12.2, Utility Syntax Guidelines
The System Interfaces volume of POSIX.1‐2008, ulimit()COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
cal and Electronics Engineers, Inc and The Open Group. (This is
POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) 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.unix.org/online.html .
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IEEE/The Open Group 2013 ULIMIT(1P)