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



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

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(1)
