Code Golf
Cat program
Since TopAnswers already [has](https://topanswers.xyz/codegolf?q=609) a post stolen from [Martin Ender](https://codegolf.stackexchange.com/questions/55422/hello-world), let's steal another one! Your task is to write a program that copies an input taken from STDIN to STDOUT. [Link](https://codegolf.stackexchange.com/questions/62230/simple-cat-program)

|  Input | Output |
Top Answer
# Polyglot ([W] and [GolfScript]), 0 bytes


Works in at least W and Golfscript [(GS: TIO)][TIO-k7am8gmc], likely more. Both languages push input to the stack and implicitly prints the stack at the end. Both accept input in any format and get converted to strings for output.

[GolfScript]: http://www.golfscript.com/golfscript/
[TIO-k7am8gmc]: https://tio.run/##S8/PSStOLsosKPkPBCEZmcUKQJSYp5CZV1BaogcA "GolfScript – Try It Online"
[W]: https://github.com/A-ee/w
Answer #2
# [Ahead], 4 bytes
This program will not write to STDOUT until STDIN is closed or empty.

    S slurp stdin to string
    U reverse string
    W write string
    @ end

[Try it online!][TIO-k7mzpytr]

[Ahead]: https://github.com/ajc2/ahead
[TIO-k7mzpytr]: https://tio.run/##S8xITUz5/z84NNzh///UgsxkBTgBAA "Ahead – Try It Online"
Answer #3
# [APL (Dyalog Unicode)], 1 [byte](https://codegolf.meta.stackexchange.com/a/9429/43319 "When can APL characters be counted as 1 byte each?") ([SBCS](https://github.com/abrudz/SBCS ".dyalog files using a single byte character set"))

Full program.


[Try it online!][TIO-k88n336w]

`⍞` prompts from stdin, with printing to stdout happening implicitly.

[APL (Dyalog Unicode)]: https://www.dyalog.com/
[TIO-k88n336w]: https://tio.run/##SyzI0U2pTMzJT///qKO94P@j3nkgxn8FMCjgSkxKTklNAwA "APL (Dyalog Unicode) – Try It Online"
Cat program
As in, you wrote it? You were the person who designed W?  Neat.
liek replying to Mathgeek
Yes, that's exactly what I mean by my language.
liek replying to Jack Douglas
I initially thought that this disobeys rule 4 of the guideline (because it's a trivial challenge).
Jack Douglas replying to liek
Your language? You mean W? [Is this your language?](https://github.com/A-ee/w
@Mathgeek Surprised that my language is already getting attention ... Do you have the interpreter already downloaded?
Jack Douglas
@liek when you flag please leave a comment in the post chat room (ie here) saying what the flag is for.
@Display Why did you flag your post?