diff -ur sed-3.02.original/doc/sed.1 sed-3.02/doc/sed.1
--- sed-3.02.original/doc/sed.1	Sun May 31 23:16:15 1998
+++ sed-3.02/doc/sed.1	Thu May  2 16:19:19 2002
@@ -25,7 +25,7 @@
 .SH SYNOPSIS
 .nf
 sed [-n] [-V] [--quiet] [--silent] [--version] [--help]
-    [-e script] [--expression=script]
+    [-u] [--unbuffered] [-e script] [--expression=script]
     [-f script-file] [--file=script-file]
     [script-if-no-other-script]
     [file...]
@@ -72,6 +72,11 @@
 .B p
 command.
 .TP
+.B -u
+.TP
+.B --unbuffered
+Forces \*(sd to turn off both input and output buffering.
+.TP
 .B -e \fIscript\fP
 .TP
 .BI --expression= script
diff -ur sed-3.02.original/doc/sed.texi sed-3.02/doc/sed.texi
--- sed-3.02.original/doc/sed.texi	Mon Jun 29 01:01:51 1998
+++ sed-3.02/doc/sed.texi	Thu May  2 16:21:11 2002
@@ -165,6 +165,12 @@
 and @sc{sed} will only produce output when explicitly told to
 via the @code{p} command.
 
address@hidden -u
address@hidden --unbuffered
address@hidden -u
address@hidden --unbuffered
+Forces @sc{sed} to turn off both input and output buffering.
+
 @item -e @var{script}
 @itemx address@hidden
 @opindex -e
diff -ur sed-3.02.original/sed/execute.c sed-3.02/sed/execute.c
--- sed-3.02.original/sed/execute.c	Mon Jul  6 06:01:01 1998
+++ sed-3.02/sed/execute.c	Thu May  2 16:13:16 2002
@@ -82,6 +82,9 @@
 /* If set, don't write out the line unless explicitly told to */
 extern flagT no_default_output;
 
+/* If set, buffer neither input nor output */
+extern flagT unbuffered;
+
 /* Do we need to be pedantically POSIX compliant? */
 extern flagT POSIXLY_CORRECT;
 
@@ -324,7 +327,6 @@
   return 1;
 }
 
-#ifdef HAVE_ISATTY
 /* fgets() doesn't let us handle NULs and fread() buffers too much
  * for interactive use.
  */
@@ -348,7 +350,6 @@
     panic("input read error: %s", strerror(errno));
   return resultlen;
 }
-#endif /*HAVE_ISATTY*/
 
 static flagT
 read_file_line(input)
@@ -369,11 +370,13 @@
       buffer.length = 0;
       if (!feof(input->fp))
 	{
+	  if (unbuffered
 #ifdef HAVE_ISATTY
-	  if (input->is_tty)
+	  || input->is_tty
+#endif
+	     )
 	    buffer.length = slow_getline(buffer.text, buffer.alloc, input->fp);
 	  else
-#endif
 	    buffer.length = ck_fread(buffer.text, 1, buffer.alloc, input->fp);
 	}
 
@@ -1046,7 +1049,7 @@
   ck_fwrite(text, 1, length, fp);
   if (nl)
     ck_fwrite("\n", 1, 1, fp);
-  if (fp != stdout)
+  if ((fp != stdout) || (unbuffered))
     ck_fflush(fp);
 }
 
diff -ur sed-3.02.original/sed/sed.c sed-3.02/sed/sed.c
--- sed-3.02.original/sed/sed.c	Fri Jul  3 03:06:26 1998
+++ sed-3.02/sed/sed.c	Thu May  2 16:09:28 2002
@@ -75,6 +75,9 @@
 /* If set, don't write out the line unless explicitly told to */
 flagT no_default_output = 0;
 
+/* If set, buffer neither input nor output */
+flagT unbuffered = 0;
+
 /* Do we need to be pedantically POSIX compliant? */
 flagT POSIXLY_CORRECT;
 
@@ -93,6 +96,8 @@
                  add the script to the commands to be executed\n\
   -f script-file, --file=script-file\n\
                  add the contents of script-file to the commands to be executed\n\
+  -u, --unbuffered\n\
+                 make stdout unbuffered\n\
       --help     display this help and exit\n\
   -V, --version  output version information and exit\n\
 \n\
@@ -117,6 +122,7 @@
     {"expression", 1, NULL, 'e'},
     {"file", 1, NULL, 'f'},
     {"quiet", 0, NULL, 'n'},
+    {"unbuffered", 0, NULL, 'u'},
     {"silent", 0, NULL, 'n'},
     {"version", 0, NULL, 'V'},
     {"help", 0, NULL, 'h'},
@@ -139,7 +145,7 @@
 #endif /*STUB_FROM_RX_LIBRARY_USAGE*/
 
   myname = *argv;
-  while ((opt = getopt_long(argc, argv, "hnrVe:f:", longopts, NULL)) != EOF)
+  while ((opt = getopt_long(argc, argv, "hnurVe:f:", longopts, NULL)) != EOF)
     {
       switch (opt)
 	{
@@ -152,7 +158,9 @@
 	case 'f':
 	  the_program = compile_file(the_program, optarg);
 	  break;
-
+	case 'u':
+	  unbuffered = 1;
+	  break;
 	case 'r':
 	  use_extended_syntax_p = 1;
 	  rx_testing = 1;
diff -ur sed-3.02.original/testsuite/help.good sed-3.02/testsuite/help.good
--- sed-3.02.original/testsuite/help.good	Tue Jun  2 04:26:56 1998
+++ sed-3.02/testsuite/help.good	Thu May  2 00:38:35 2002
@@ -6,6 +6,8 @@
                  add the script to the commands to be executed
   -f script-file, --file=script-file
                  add the contents of script-file to the commands to be executed
+  -u, --unbuffered
+                 make stdout unbuffered
       --help     display this help and exit
   -V, --version  output version information and exit