Fix 2004/sds/try.sh for README.md changes

Commit cbc022d864 which edited
2004/sds/README.md broke the functionality of one of the features of the
code so the previous revision of README.md was copied to README_sds.md
and the script now uses that file.

This does mean the manifest is out of date and that will have to be
fixed another time but now the script works okay. Without this one of
the files to be compiled does not compile at all and it seems better
this way than to tamper with the code especially given what the entry
does and because it would take more time to fix anyway.

2004/sds/README.md

@@ -117,16 +117,11 @@ reasonable compiler.  In particular, they are known to compile under
 GNU C.
 
 
-<!--
+## Copyright and CC BY-SA 4.0 License:
 
-    Copyright © 1984-2024 by Landon Curt Noll. All Rights Reserved.
+This file is Copyright (c) 2023 by Landon Curt Noll.  All Rights Reserved.
+You are free to share and adapt this file under the terms of this license:
 
-    You are free to share and adapt this file under the terms of this license:
+    Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
 
-	Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
-
-    For more information, see:
-
-	https://creativecommons.org/licenses/by-sa/4.0/
-
--->
+For more information, see: https://creativecommons.org/licenses/by-sa/4.0/

2004/sds/README_sds.md

@@ -0,0 +1,127 @@
+## To build:
+
+```sh
+make
+```
+
+
+### Bugs and (Mis)features:
+
+The current status of this entry is:
+
+```
+STATUS: INABIAF - please **DO NOT** fix
+```
+
+For more detailed information see [2004 sds bugs](../../bugs.html#2004_sds).
+
+
+## To use:
+
+```sh
+./sds
+```
+
+
+## Try:
+
+```sh
+./try.sh
+```
+
+
+## Judges' remarks:
+
+Why not use the program to hide another program in the program? It
+must have seemed reasonable at the time.
+
+The ability to hide a message in plain text is quite charming, really.
+We must admit to a bit of uncertainty about where you'd find such
+messages, or how useful they'd be.  Or, of course, whether all those
+horribly badly formatted emails spammers send might contain secret
+messages.  Annoyingly, it's a little too obvious that SOMETHING has
+been done to a message for us to hide one in the remarks.  :)
+
+
+## Author's remarks:
+
+[Steganography](https://en.wikipedia.org/wiki/Steganography) is the term for the
+family of techniques used for hiding information within other information.
+Today, it has many real world uses, particularly for digital watermarking.
+
+This program uses a steganographic technique to hide information in any text
+file.  The specific technique used is aimed at writers of obfuscated programs
+for the IOCCC, as the hidden information is encoded in the whitespace in the
+source file.  As we know, there are up to an additional 2048 characters of
+whitespace available to entrants to the IOCCC, so it turns out that this is an
+ideal place to hide things.
+
+The program as provided is the steganographic decoder.  Rather than
+provide a separate encoding program, you should not be surprised to
+learn that I opted to steganographically hide the encoder inside the
+decoder.
+
+Try it out.  Compile the program, then type
+
+```sh
+./sds < sds.c
+```
+
+You should see the encoder program displayed.  Now save it, like:
+
+```sh
+./sds < sds.c > encoder.c
+```
+
+Then compile `encoder.c`.  You now have the complete system ready.
+
+The encoder expects to get a filename as an argument.  This filename
+is the name of the file containing the information to be hidden.  It
+expects the file in which to hide the information to be on the
+standard input, and will output the results on the standard output.
+
+You can use it like this (assuming you have a file called remarks):
+
+```sh
+echo 'Hello, World!' > message
+./encoder message < remarks > remarks_msg
+```
+
+Then to decode:
+
+```sh
+./sds < remarks_msg
+Hello, World!
+```
+
+C programs are mostly unaffected by adding steganographic content,
+but it is possible in certain circumstances for whitespace to be
+changed inside strings where it should be left alone.  Plain text
+files are good candidates for hiding information in, but the added
+spacing may render the text somewhat difficult to read.
+
+
+### Obfuscation
+
+This program is obfuscated in a number of ways:
+
+* The code is all but impossible to read due to the spacing.
+* The algorithm is well hidden in the code due to copious red-herrings.
+* The long expressions cause indentation tools to give poor results.
+* And good old fashioned ternary operators are the icing on the cake.
+
+### Compiling the program
+
+The program (and the encoder program) should compile on any
+reasonable compiler.  In particular, they are known to compile under
+GNU C.
+
+
+## Copyright and CC BY-SA 4.0 License:
+
+This file is Copyright (c) 2023 by Landon Curt Noll.  All Rights Reserved.
+You are free to share and adapt this file under the terms of this license:
+
+    Creative Commons Attribution-ShareAlike 4.0 International (CC BY-SA 4.0)
+
+For more information, see: https://creativecommons.org/licenses/by-sa/4.0/

2004/sds/try.sh

@@ -30,10 +30,10 @@ echo 1>&2
 make encoder 2>/dev/null
 echo 1>&2
 
-echo "$ ./encoder README.md <sds.c | tee sds_msg.c" 1>&2
+echo "$ ./encoder README_sds.md <sds.c | tee sds_msg.c" 1>&2
 read -r -n 1 -p "Press any key to continue (space = next page, q = quit): "
 echo 1>&2
-./encoder README.md <sds.c | tee sds_msg.c | less -rEXFK
+./encoder README_sds.md <sds.c | tee sds_msg.c | less -rEXFK
 
 read -r -n 1 -p "Press any key to run: make sds_msg 2>/dev/null: "
 echo 1>&2
@@ -55,15 +55,15 @@ echo 1>&2
 echo 'Hello, World!' > message
 echo 1>&2
 
-echo "$ ./encoder message < README.md | tee remarks.md" 1>&2
+echo "$ ./encoder message < README_sds.md | tee remarks.md" 1>&2
 read -r -n 1 -p "Press any key to continue (space = next page, q = quit): "
 echo 1>&2
-./encoder message < README.md | tee remarks.md | less -rEXFK
+./encoder message < README_sds.md | tee remarks.md | less -rEXFK
 echo 1>&2
 
-read -r -n 1 -p "Press any key to run: diff remarks.md README.md (space = next page, q = quit): "
+read -r -n 1 -p "Press any key to run: diff remarks.md README_sds.md (space = next page, q = quit): "
 echo 1>&2
-diff remarks.md README.md | less -rEXFK
+diff remarks.md README_sds.md | less -rEXFK
 echo "Did you notice how similar they are?" 1>&2
 echo 1>&2