document supported options better, add a short info about

this awk on start of DESCRIPTION section

usr.bin/awk/awk.1

@@ -1,4 +1,4 @@
-.\"	$NetBSD: awk.1,v 1.3 2001/02/04 20:47:50 jdolecek Exp $
+.\"	$NetBSD: awk.1,v 1.4 2001/02/05 13:23:57 jdolecek Exp $
 .\"
 .\" Copyright (C) Lucent Technologies 1997
 .\" All Rights Reserved
@@ -32,17 +32,28 @@
 .Nm
 .Op Fl F Ar fs
 .Op Fl v Ar var=value
-.Op Ar prog | Fl f Ar progname
+.Op Fl safe
+.Op Fl d[N]
+.Op Ar prog | Fl f Ar filename
 .Ar
+.Nm ""
+.Fl V
 .Sh DESCRIPTION
 .Nm
+is the Bell Labs' implementation of the AWK programming language as
+described in the
+.Em The AWK Programming Language
+by
+A. V. Aho, B. W. Kernighan, and P. J. Weinberger.
+.Pp
+.Nm
 scans each input
 .Ar file
 for lines that match any of a set of patterns specified literally in
 .Ar prog
 or in one or more files
 specified as
-.Fl f Ar progfile .
+.Fl f Ar filename .
 With each pattern
 there can be an associated action that will be performed
 when a line of a
@@ -60,20 +71,48 @@ of the form
 .Ar var=value
 is treated as an assignment, not a filename,
 and is executed at the time it would have been opened if it were a filename.
-The option
-.Fl v
-followed by
-.Ar var=value
-is an assignment to be done before
+.Pp
+The options are as follows:
+.Bl -tag -width indent
+.It Fl d[N]
+Set debug level to specified number
+.Ar N .
+If the number is omitted, debug level is set to 1.
+.It Fl f Ar filename
+Read the AWK program source from specified file
+.Ar filename ,
+instead of the first command line argument.
+Multiple
+.Fl f
+options may be specified.
+.It Fl F Ar fs
+Set the input field separator
+.Va FS
+to the regular expression
+.Ar fs .
+.It Fl mr Ar NNN , Fl mf Ar NNN
+Obsolete, no longer needed options. Set limit on maximum record or
+fields number.
+.It Fl safe
+Potentially unsafe functions such as
+.Fn system
+make the program abort (with a warning message).
+.It Fl v
+Assign the value
+.Ar value
+to the variable
+.Va var
+before
 .Ar prog
-is executed;
-any number of
+is executed.
+Any number of
 .Fl v
 options may be present.
-The
-.Fl F Ar fs
-option defines the input field separator to be the regular expression
-.Ar fs.
+.It Fl V
+Print
+.Nm
+version on standard output and exit.
+.El
 .Pp
 An input line is normally made up of fields separated by white space,
 or by regular expression