1UNAME(1P)                  POSIX Programmer's Manual                 UNAME(1P)
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PROLOG

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.
10

NAME

12       uname — return system name
13

SYNOPSIS

15       uname [-amnrsv]
16

DESCRIPTION

18       By default, the uname utility shall write the operating system name  to
19       standard  output.  When options are specified, symbols representing one
20       or more system characteristics shall be written to the standard output.
21       The  format  and contents of the symbols are implementation-defined. On
22       systems conforming to the System Interfaces volume of POSIX.1‐2017, the
23       symbols  written  shall  be  those supported by the uname() function as
24       defined in the System Interfaces volume of POSIX.1‐2017.
25

OPTIONS

27       The uname utility shall conform  to  the  Base  Definitions  volume  of
28       POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
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30       The following options shall be supported:
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32       -a        Behave as though all of the options -mnrsv were specified.
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34       -m        Write  the  name  of the hardware type on which the system is
35                 running to standard output.
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37       -n        Write the name of this node within an  implementation-defined
38                 communications network.
39
40       -r        Write  the  current  release  level  of  the operating system
41                 implementation.
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43       -s        Write the name of the implementation of the operating system.
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45       -v        Write the current version level of this release of the  oper‐
46                 ating system implementation.
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48       If  no options are specified, the uname utility shall write the operat‐
49       ing system name, as if the -s option had been specified.
50

OPERANDS

52       None.
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STDIN

55       Not used.
56

INPUT FILES

58       None.
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ENVIRONMENT VARIABLES

61       The following environment  variables  shall  affect  the  execution  of
62       uname:
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64       LANG      Provide  a  default  value for the internationalization vari‐
65                 ables that are unset or null. (See the Base Definitions  vol‐
66                 ume  of POSIX.1‐2017, Section 8.2, Internationalization Vari‐
67                 ables for the precedence  of  internationalization  variables
68                 used to determine the values of locale categories.)
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70       LC_ALL    If  set  to  a non-empty string value, override the values of
71                 all the other internationalization variables.
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73       LC_CTYPE  Determine the locale for the interpretation of  sequences  of
74                 bytes of text data as characters (for example, single-byte as
75                 opposed to multi-byte characters in arguments).
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77       LC_MESSAGES
78                 Determine the locale that should be used to affect the format
79                 and  contents  of  diagnostic  messages  written  to standard
80                 error.
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82       NLSPATH   Determine the location of message catalogs for the processing
83                 of LC_MESSAGES.
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ASYNCHRONOUS EVENTS

86       Default.
87

STDOUT

89       By default, the output shall be a single line of the following form:
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91
92           "%s\n", <sysname>
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94       If the -a option is specified, the output shall be a single line of the
95       following form:
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98           "%s %s %s %s %s\n", <sysname>, <nodename>, <release>,
99               <version>, <machine>
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101       Additional implementation-defined symbols may be written; all such sym‐
102       bols shall be written at the end of the line of output before the <new‐
103       line>.
104
105       If options are specified to select different combinations of  the  sym‐
106       bols, only those symbols shall be written, in the order shown above for
107       the -a option. If a symbol is not selected for writing, its correspond‐
108       ing trailing <blank> characters also shall not be written.
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STDERR

111       The standard error shall be used only for diagnostic messages.
112

OUTPUT FILES

114       None.
115

EXTENDED DESCRIPTION

117       None.
118

EXIT STATUS

120       The following exit values shall be returned:
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122        0    The requested information was successfully written.
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124       >0    An error occurred.
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CONSEQUENCES OF ERRORS

127       Default.
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129       The following sections are informative.
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APPLICATION USAGE

132       Note that any of the symbols could include embedded <space> characters,
133       which may affect parsing algorithms if multiple  options  are  selected
134       for output.
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136       The  node  name  is  typically  a name that the system uses to identify
137       itself for inter-system communication addressing.
138

EXAMPLES

140       The following command:
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142
143           uname -sr
144
145       writes the operating system name and release level, separated by one or
146       more <blank> characters.
147

RATIONALE

149       It  was  suggested  that this utility cannot be used portably since the
150       format of the symbols is implementation-defined.  The  POSIX.1  working
151       group  could  not  achieve  consensus  on defining these formats in the
152       underlying uname() function, and there was  no  expectation  that  this
153       volume  of POSIX.1‐2017 would be any more successful. Some applications
154       may still find this historical utility of value. For example, the  sym‐
155       bols could be used for system log entries or for comparison with opera‐
156       tor or user input.
157

FUTURE DIRECTIONS

159       None.
160

SEE ALSO

162       The Base Definitions volume of  POSIX.1‐2017,  Chapter  8,  Environment
163       Variables, Section 12.2, Utility Syntax Guidelines
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165       The System Interfaces volume of POSIX.1‐2017, uname()
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168       Portions  of  this text are reprinted and reproduced in electronic form
169       from IEEE Std 1003.1-2017, Standard for Information Technology --  Por‐
170       table  Operating System Interface (POSIX), The Open Group Base Specifi‐
171       cations Issue 7, 2018 Edition, Copyright (C) 2018 by the  Institute  of
172       Electrical  and  Electronics Engineers, Inc and The Open Group.  In the
173       event of any discrepancy between this version and the original IEEE and
174       The  Open Group Standard, the original IEEE and The Open Group Standard
175       is the referee document. The original Standard can be  obtained  online
176       at http://www.opengroup.org/unix/online.html .
177
178       Any  typographical  or  formatting  errors that appear in this page are
179       most likely to have been introduced during the conversion of the source
180       files  to  man page format. To report such errors, see https://www.ker
181       nel.org/doc/man-pages/reporting_bugs.html .
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185IEEE/The Open Group                  2017                            UNAME(1P)
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