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.\"	@(#)uname.1	8.3 (Berkeley) 4/8/94
.\" $FreeBSD$
.\"
.Dd November 20, 2013
.Dt UNAME 1
.Os
.Sh NAME
.Nm uname
.Nd display information about the system
.Sh SYNOPSIS
.Nm
.Op Fl aiKmnoprsUv
.Sh DESCRIPTION
The
.Nm
command writes the name of the operating system implementation to
standard output.
When options are specified, strings representing one or more system
characteristics are written to standard output.
.Pp
The options are as follows:
.Bl -tag -width indent
.It Fl a
Behave as though the options
.Fl m , n , r , s ,
and
.Fl v
were specified.
.It Fl i
Write the kernel ident to standard output.
.It Fl K
Write the
.Fx
version of the kernel.
.It Fl m
Write the type of the current hardware platform to standard output.
.It Fl n
Write the name of the system to standard output.
.It Fl o
This is a synonym for the
.Fl s
option, for compatibility with other systems.
.It Fl p
Write the type of the machine processor architecture to standard output.
.It Fl r
Write the current release level of the operating system
to standard output.
.It Fl s
Write the name of the operating system implementation to standard output.
.It Fl U
Write the
.Fx
version of the user environment.
.It Fl v
Write the version level of this release of the operating system
to standard output.
.El
.Pp
If the
.Fl a
flag is specified, or multiple flags are specified, all
output is written on a single line, separated by spaces.
.Pp
The
.Fl K
and
.Fl U
flags are intended to be used for fine grain differentiation of incremental
.Fx
development and user visible changes.
.Sh ENVIRONMENT
An environment variable composed of the string
.Ev UNAME_
followed by any flag to the
.Nm
utility (except for
.Fl a )
will allow the corresponding data to be set to the contents
of the environment variable.
.Sh EXIT STATUS
.Ex -std
.Sh SEE ALSO
.Xr feature_present 3 ,
.Xr getosreldate 3 ,
.Xr sysctl 3 ,
.Xr uname 3 ,
.Xr sysctl 8
.Sh STANDARDS
The
.Nm
command is expected to conform to the
.St -p1003.2
specification.
.Sh HISTORY
The
.Nm
command appeared in PWB UNIX.
.Pp
The
.Fl K
and
.Fl U
extension flags appeared in
.Fx 10.0 .