The Open Group Base Specifications Issue 7
IEEE Std 1003.1-2008, 2016 Edition
Copyright © 2001-2016 The IEEE and The Open Group

#### NAME

> ulimit - set or report file size limit

#### SYNOPSIS

> ``[XSI] 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 XBD 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 XBD 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

> XBD Environment Variables, Utility Syntax Guidelines

> XSH ulimit

#### CHANGE HISTORY

> First released in Issue 2.

#### Issue 7

> SD5-XCU-ERN-97 is applied, updating the SYNOPSIS.

End of informative text.

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