ULIMIT(1)                  POSIX Programmer's Manual                 ULIMIT(1)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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
       POSIX.1-2017, 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 POSIX.1-2017, 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 Base Definitions volume of POSIX.1-2017, Chapter _8, Environment
       Variables, Section 12.2, Utility Syntax Guidelines

       The System Interfaces volume of POSIX.1-2017, ulimit()

COPYRIGHT
       Portions of this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1-2017, Standard for Information Technology --
       Portable Operating System Interface (POSIX), The Open Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 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 .

       Any typographical or formatting errors that appear in this page are
       most likely to have been introduced during the conversion of the source
       files to man page format. To report such errors, see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .



IEEE/The Open Group                  2017                            ULIMIT(1)
