document -T and TMPDIR handling

resurrect ENVIRONMENT and FILES, adjust to be more correct
slighly adjust SYNOPSIS line, so that it looks little nicer :)

usr.bin/sort/sort.1

@@ -1,4 +1,4 @@
-.\"	$NetBSD: sort.1,v 1.13 2001/02/07 21:13:36 jdolecek Exp $
+.\"	$NetBSD: sort.1,v 1.14 2001/02/19 16:27:04 jdolecek Exp $
 .\"
 .\" Copyright (c) 1991, 1993
 .\"	The Regents of the University of California.  All rights reserved.
@@ -51,10 +51,9 @@
 .Fl k
 .Ar field1 Ns Op Li \&, Ns Ar field2
 .Oc
-.Ar ...
+.Op Fl T Ar dir
 .Op Fl o Ar output
-.Op Ar file
-.Ar ...
+.Op Ar
 .Sh DESCRIPTION
 The
 .Nm
@@ -88,6 +87,16 @@ file to
 be used instead of the standard output.
 This file
 can be the same as one of the input files.
+.It Fl T Ar dir
+Use
+.Ar dir
+as the directory for temporary files.  The default is the
+value specified in the environment variable
+.Ev TMPDIR or
+.Pa /tmp
+if
+.Ev TMPDIR
+is not defined.
 .It Fl u
 Unique: suppress all but one in each set of lines
 having equal keys.
@@ -346,6 +355,32 @@ option
 .It 2
 an error occurred.
 .El
+.Sh ENVIRONMENT
+If the following environment variable exists, it is utilized by
+.Nm "" .
+.Bl -tag -width Ev
+.It Ev TMPDIR
+.Nm
+uses the contents of the
+.Ev TMPDIR
+environment variable as the path in which to store
+temporary files.
+.El
+.Sh FILES
+.Bl -tag -width outputNUMBER+some -compact
+.It Pa /tmp/sort.*
+Default temporary files.
+.It Pa Ar output Ns NUMBER
+Temporary file which is used for output if
+.Ar output
+already exists. Once sorting is finished, this file
+replaces
+.Ar output
+(via
+.Xr link 2
+and
+.Xr unlink 2 ).
+.El
 .Sh SEE ALSO
 .Xr comm 1 ,
 .Xr uniq 1 ,