uname

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



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
       uname — return system name

SYNOPSIS
       uname [-amnrsv]

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

OPTIONS
       The uname utility shall conform to the Base Definitions volume of
       POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.

       The following options shall be supported:

       -a        Behave as though all of the options -mnrsv were specified.

       -m        Write the name of the hardware type on which the system is
                 running to standard output.

       -n        Write the name of this node within an implementation-defined
                 communications network.

       -r        Write the current release level of the operating system
                 implementation.

       -s        Write the name of the implementation of the operating system.

       -v        Write the current version level of this release of the
                 operating system implementation.

       If no options are specified, the uname utility shall write the operating
       system name, as if the -s option had been specified.

OPERANDS
       None.

STDIN
       Not used.

INPUT FILES
       None.

ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of uname:

       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
       By default, the output shall be a single line of the following form:


           "%s\n", <sysname>

       If the -a option is specified, the output shall be a single line of the
       following form:


           "%s %s %s %s %s\n", <sysname>, <nodename>, <release>,
               <version>, <machine>

       Additional implementation-defined symbols may be written; all such
       symbols shall be written at the end of the line of output before the
       <newline>.

       If options are specified to select different combinations of the symbols,
       only those symbols shall be written, in the order shown above for the -a
       option. If a symbol is not selected for writing, its corresponding
       trailing <blank> characters also shall not be written.

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    The requested information was successfully written.

       >0    An error occurred.

CONSEQUENCES OF ERRORS
       Default.

       The following sections are informative.

APPLICATION USAGE
       Note that any of the symbols could include embedded <space> characters,
       which may affect parsing algorithms if multiple options are selected for
       output.

       The node name is typically a name that the system uses to identify itself
       for inter-system communication addressing.

EXAMPLES
       The following command:


           uname -sr

       writes the operating system name and release level, separated by one or
       more <blank> characters.

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

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, uname()

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                             UNAME(1P)