# ulimit

## PROLOG



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


## 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.
    


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