Index: usr.bin/sed/main.c
===================================================================
--- usr.bin/sed/main.c
+++ usr.bin/sed/main.c
@@ -56,6 +56,7 @@
 #include <libgen.h>
 #include <limits.h>
 #include <locale.h>
+#include <getopt.h>
 #include <regex.h>
 #include <stddef.h>
 #define _WITH_GETLINE
@@ -121,6 +122,21 @@
 static void add_file(char *);
 static void usage(void);
 
+static struct option longopts[] = {
+	{"regexp-extended",	no_argument,		NULL,	'E'},
+	{"in-place-separate",	optional_argument,	NULL,	'I'},
+	{"truncate",		no_argument,		NULL,	'a'},
+	{"expression",		required_argument,	NULL,	'e'},
+	{"file",		required_argument,	NULL,	'f'},
+	{"in-place",		optional_argument,	NULL,	'i'},
+	{"line-buffered",	no_argument,		NULL,	'l'},
+	{"quiet",		no_argument,		NULL,	'n'},
+	{"silent",		no_argument,		NULL,	'n'}, /* GNU compat */
+	/* r is for GNU compat */
+	{"unbuffered",		no_argument,		NULL,	'u'},
+	{NULL,			0,			NULL,	0}, 
+};
+
 int
 main(int argc, char *argv[])
 {
@@ -131,16 +147,22 @@
 
 	fflag = 0;
 	inplace = NULL;
+	ispan = 0;
 
-	while ((c = getopt(argc, argv, "EI:ae:f:i:lnru")) != -1)
+	while ((c = getopt_long(argc, argv, "EI::ae:f:i::lnru", longopts, NULL)) != -1)
 		switch (c) {
 		case 'r':		/* Gnu sed compat */
 		case 'E':
 			rflags = REG_EXTENDED;
 			break;
 		case 'I':
-			inplace = optarg;
-			ispan = 1;	/* span across input files */
+			ispan = 1;
+			/* FALLTHROUGH */
+		case 'i':
+			if (optarg)
+				inplace = optarg;
+			else
+				inplace = "";
 			break;
 		case 'a':
 			aflag = 1;
@@ -157,10 +179,6 @@
 			fflag = 1;
 			add_compunit(CU_FILE, optarg);
 			break;
-		case 'i':
-			inplace = optarg;
-			ispan = 0;	/* don't span across input files */
-			break;
 		case 'l':
 			if(setvbuf(stdout, NULL, _IOLBF, 0) != 0)
 				warnx("setting line buffered output failed");
@@ -204,8 +222,8 @@
 usage(void)
 {
 	(void)fprintf(stderr,
-	    "usage: %s script [-Ealnru] [-i extension] [file ...]\n"
-	    "\t%s [-Ealnu] [-i extension] [-e script] ... [-f script_file]"
+	    "usage: %s script [-Ealnru] [-I [extension]] [-i [extension]] [file ...]\n"
+	    "\t%s [-Ealnu] [-I [extension]] [-i [extension]] [-e script] ... [-f script_file]"
 	    " ... [file ...]\n", getprogname(), getprogname());
 	exit(1);
 }
Index: usr.bin/sed/sed.1
===================================================================
--- usr.bin/sed/sed.1
+++ usr.bin/sed/sed.1
@@ -46,8 +46,8 @@
 .Op Fl Ealnr
 .Op Fl e Ar command
 .Op Fl f Ar command_file
-.Op Fl I Ar extension
-.Op Fl i Ar extension
+.Op Fl I Bo Ar extension Bc
+.Op Fl i Bo Ar extension Bc
 .Op Ar
 .Sh DESCRIPTION
 The
@@ -68,13 +68,13 @@
 .Pp
 The following options are available:
 .Bl -tag -width indent
-.It Fl E
+.It Fl E , Fl -regexp-extended
 Interpret regular expressions as extended (modern) regular expressions
 rather than basic regular expressions (BRE's).
 The
 .Xr re_format 7
 manual page fully describes both formats.
-.It Fl a
+.It Fl a , Fl -truncate
 The files listed as parameters for the
 .Dq w
 functions are created (or truncated) before any processing begins,
@@ -86,23 +86,23 @@
 to delay opening each file until a command containing the related
 .Dq w
 function is applied to a line of input.
-.It Fl e Ar command
+.It Fl e Ar command No , Fl -expression Ar command
 Append the editing commands specified by the
 .Ar command
 argument
 to the list of commands.
-.It Fl f Ar command_file
+.It Fl f Ar command_file No , Fl -file Ar command_file
 Append the editing commands found in the file
 .Ar command_file
 to the list of commands.
 The editing commands should each be listed on a separate line.
-.It Fl I Ar extension
+.It Fl I Bo Ar extension Bc No , Fl -in-place-separate Bo Ar extension Bc
 Edit files in-place, saving backups with the specified
 .Ar extension .
-If a zero-length
+If no or a zero-length
 .Ar extension
 is given, no backup will be saved.
-It is not recommended to give a zero-length
+It recommended to provide an
 .Ar extension
 when in-place editing files, as you risk corruption or partial content
 in situations where disk space is exhausted, etc.
@@ -122,7 +122,7 @@
 where using
 .Fl i
 is desired.
-.It Fl i Ar extension
+.It Fl i Bo Ar extension Bc No , Fl -in-place Bo Ar extension Bc
 Edit files in-place similarly to
 .Fl I ,
 but treat each file independently from other files.
@@ -136,9 +136,9 @@
 The net result is as though each file were edited by a separate
 .Nm
 instance.
-.It Fl l
+.It Fl l No , Fl -line-buffered
 Make output line buffered.
-.It Fl n
+.It Fl n No , Fl -quiet , Fl -silent
 By default, each line of input is echoed to the standard output after
 all of the commands have been applied to it.
 The
@@ -148,7 +148,7 @@
 Same as
 .Fl E
 for compatibility with GNU sed.
-.It Fl u
+.It Fl u No , Fl -unbuffered
 Make output unbuffered.
 .El
 .Pp