freebsd/usr.bin/getconf/getconf.1

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.Dd April 25, 2000
.Dt GETCONF 1
.Os
.Sh NAME
.Nm getconf
.Nd retrieve standard configuration variables
.Sh SYNOPSIS
.Nm
.Op Fl v Ar environment
.Ar path_var
.Ar file
.Pp
.Nm
.Op Fl v Ar environment
.Ar system_var
.Sh DESCRIPTION
The
.Nm
utility prints the value of a
.Tn POSIX
or
.Tn X/Open
path or system configuration variable to the standard output.
If the specified variable is undefined, the string
.Dq Li undefined
is output.
.Pp
The first form of the command, with two mandatory
arguments, retrieves file- and filesystem-specific
configuration variables using
.Xr pathconf 2 .
The second form, with a single argument, retrieves system
configuration variables using
.Xr confstr 3
and
.Xr sysconf 3 ,
depending on the type of variable.
.Pp
All variables use the same name as the manifest constants defined in
the relevant standard C-language bindings, including any leading
underscore or prefix.
That is to say,
.Ar system_var
might be
.Dv ARG_MAX
or
.Dv _POSIX_VERSION ,
as opposed to the
.Xr sysconf 3
names
.Dv _SC_ARG_MAX
or
.Dv _SC_POSIX_VERSION .
(There is one exception: there is no corresponding manifest constant
to
.Dv _CS_PATH ,
so a
.Ar system_var
of
.Dq Li PATH 
is used.)
.Pp
The
.Fl v Ar environment
option is not supported, but provided for compatibility purposes.
.Sh DIAGNOSTICS
The
.Nm
utility exits 0 on success or >0 if an error occurred.
Use of a
.Ar system_var
or
.Ar path_var
which is completely unknown to the system is considered an error,
causing a diagnostic message to be written to standard error; one
which is known but merely undefined does not result in an error
indication.
.Pp
Use of the unsupported
.Fl v Ar environment
option will result in a diagnostic message indicating that it is not
supported.
.Sh EXAMPLES
The command:
.Bd -literal -offset indent
getconf PATH
.Ed
.Pp
will display the system default setting for the
.Ev PATH
environment variable.
.Pp
The command:
.Bd -literal -offset indent
getconf NAME_MAX /tmp
.Ed
.Pp
will display the maximum length of a filename in the
.Pa /tmp
directory.
.Sh SEE ALSO
.Xr confstr 3 ,
.Xr pathconf 2 ,
.Xr sysconf 3
.Sh STANDARDS
The
.Nm
utility is expected to be compliant with
.St -susv2 .
.Sh HISTORY
The
.Nm
command first appeared in
.Fx 5.0 .
.Sh AUTHORS
.An Garrett A. Wollman Aq wollman@lcs.mit.edu