NAME
uname - return system name
SYNOPSIS
uname [-snrvma]
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
IEEE Std 1003.1-2001, the symbols written shall be those supported by
the uname() function as defined in the System Interfaces volume of
IEEE Std 1003.1-2001.
OPTIONS
The uname utility shall conform to the Base Definitions volume of
IEEE Std 1003.1-2001, 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
IEEE Std 1003.1-2001, 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>s 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>s, 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>s.
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 IEEE Std 1003.1-2001 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 System Interfaces volume of IEEE Std 1003.1-2001, uname()
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 6, Copyright (C) 2001-2003 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 .