1ULIMIT(1P) POSIX Programmer's Manual ULIMIT(1P)
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6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
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12 ulimit — set or report file size limit
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15 ulimit [-f] [blocks]
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18 The ulimit utility shall set or report the file-size writing limit
19 imposed on files written by the shell and its child processes (files of
20 any size may be read). Only a process with appropriate privileges can
21 increase the limit.
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24 The ulimit utility shall conform to the Base Definitions volume of
25 POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
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27 The following option shall be supported:
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29 -f Set (or report, if no blocks operand is present), the file
30 size limit in blocks. The -f option shall also be the default
31 case.
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34 The following operand shall be supported:
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36 blocks The number of 512-byte blocks to use as the new file size
37 limit.
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40 Not used.
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43 None.
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46 The following environment variables shall affect the execution of
47 ulimit:
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49 LANG Provide a default value for the internationalization vari‐
50 ables that are unset or null. (See the Base Definitions vol‐
51 ume of POSIX.1‐2017, Section 8.2, Internationalization Vari‐
52 ables for the precedence of internationalization variables
53 used to determine the values of locale categories.)
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55 LC_ALL If set to a non-empty string value, override the values of
56 all the other internationalization variables.
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58 LC_CTYPE Determine the locale for the interpretation of sequences of
59 bytes of text data as characters (for example, single-byte as
60 opposed to multi-byte characters in arguments).
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62 LC_MESSAGES
63 Determine the locale that should be used to affect the format
64 and contents of diagnostic messages written to standard
65 error.
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67 NLSPATH Determine the location of message catalogs for the processing
68 of LC_MESSAGES.
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71 Default.
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74 The standard output shall be used when no blocks operand is present. If
75 the current number of blocks is limited, the number of blocks in the
76 current limit shall be written in the following format:
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79 "%d\n", <number of 512-byte blocks>
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81 If there is no current limit on the number of blocks, in the POSIX
82 locale the following format shall be used:
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85 "unlimited\n"
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88 The standard error shall be used only for diagnostic messages.
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91 None.
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94 None.
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97 The following exit values shall be returned:
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99 0 Successful completion.
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101 >0 A request for a higher limit was rejected or an error occurred.
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104 Default.
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106 The following sections are informative.
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109 Since ulimit affects the current shell execution environment, it is
110 always provided as a shell regular built-in. If it is called in a sepa‐
111 rate utility execution environment, such as one of the following:
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114 nohup ulimit -f 10000
115 env ulimit 10000
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117 it does not affect the file size limit of the caller's environment.
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119 Once a limit has been decreased by a process, it cannot be increased
120 (unless appropriate privileges are involved), even back to the original
121 system limit.
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124 Set the file size limit to 51200 bytes:
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127 ulimit -f 100
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130 None.
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133 None.
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136 The Base Definitions volume of POSIX.1‐2017, Chapter 8, Environment
137 Variables, Section 12.2, Utility Syntax Guidelines
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139 The System Interfaces volume of POSIX.1‐2017, ulimit()
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142 Portions of this text are reprinted and reproduced in electronic form
143 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
144 table Operating System Interface (POSIX), The Open Group Base Specifi‐
145 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
146 Electrical and Electronics Engineers, Inc and The Open Group. In the
147 event of any discrepancy between this version and the original IEEE and
148 The Open Group Standard, the original IEEE and The Open Group Standard
149 is the referee document. The original Standard can be obtained online
150 at http://www.opengroup.org/unix/online.html .
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152 Any typographical or formatting errors that appear in this page are
153 most likely to have been introduced during the conversion of the source
154 files to man page format. To report such errors, see https://www.ker‐
155 nel.org/doc/man-pages/reporting_bugs.html .
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159IEEE/The Open Group 2017 ULIMIT(1P)