ULIMIT(P) POSIX Programmer's Manual ULIMIT(P)
ulimit - set or report file size limit
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 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.
The following operand shall be supported:
blocks The number of 512-byte blocks to use as the new file size limit.
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.
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 error.
Determine the location of message catalogs for the processing of LC_MESSAGES .
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 origi-
nal system limit.
Set the file size limit to 51200 bytes:
ulimit -f 100
The System Interfaces volume of IEEE Std 1003.1-2001, ulimit()
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 ULIMIT(P)