Shortest code to produce infinite output

Question

Write the shortest code you can that produces an infinite output.

That's all. You code will only be disqualified if it stops producing output at some point. As always in code golf, the shortest code wins.

Here's a list of answers that I think are really clever, so they can get credit:

• The comma is both code and data
• Infinite errors (that counts)
• Infinite warnings (that also counts)
• What's Marbelous?

Leaderboard

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Answer 1

BASIC

10 PRINT "HELLO WORLD"
20 GOTO 10

Answer 2

Postscript 9

{1 =}loop

Output 1 in an infinite loop.

Answer 3

C, 20 bytes (competing according to the challenge's creator)

Suppose the following code is contained in e.c:

int i;
#include"e.c"

In a machine with infinite system resources, GCC will create an infinitely big temporary file trying to resolve a recursive #inclusion.

Answer 4

C, 26 25 24 (no recursion)

main(){for(;;puts(""));}

Prints endless '\n' characters. This is a byte longer than the shortest C answer, but doesn't rely on tail call optimization to avoid overflowing the stack.

Answer 5

R, 13 characters

repeat cat(1)

Answer 6

PowerShell 2.0: 17 11 8

My initial solution:

while(1 -eq 1){1}

Thanks to r.e.s.:

while(1){1}

I think Danko Durbić has the winner, here. I'm not even sure why this should work, but it does and I can't think of anything shorter so far.

for(){1}

Answer 7

C#, 57

Another C# entry, with a twist:

class M{static int Main(){for(;;)System.Console.Beep();}}

This interpretation of "output" may be stretching, but still valid I think (and saves 4 characters! :)

Answer 8

Xojo, 18 12 chars

Again, please don't actually run this (same reason as the JavaScript answer):

do
Beep
loop

Never said the output couldn't be audio...

Answer 9

Windows Batch File, 1 character

Create a file called a.bat containing:

a

When you execute this batch file, it executes itself. The Windows Command Prompt by default echos every command to the console, so the output resembles:

C:\>a

C:\>a

C:\>a

C:\>a

Answer 10

Python, 17 13

while 1:print

Thanks to Ben and r.e.s.

Answer 11

sed 7 5 chars (version 4.2)

sed -e ':;p;b' <<<'Hello world!'

Unfortunely, this won't work anymore, from version 4.4 of GNU sed:

sed -e ':a;p;ba' <<<'Hello world!'

Answer 12

Perl 6, 13 11 characters

Using some nice Perl6 syntax for infinite lazy lists:

.say for ^∞

The code will print all integers from 0 upto infinity or until RAM runs out to store single big integers, whichever comes first.

Answer 13

Microsoft Word Math AutoCorrect, 4 bytes

1. Add a new entry in the Math AutoCorrect table (not the regular one): $ -> $$. This makes a new production rule for us. (3 bytes)
2. Insert an Equation (Alt + =), and type a single $. The AutoCorrect will replace it with a $$, but that's not you inputting any extra characters, so it doesn't add to the byte count. This initializes our memory tape. (1 byte)
3. Press the "Professional" button under Equation Tools. This is where the program officially starts running.
4. Watch the little right-moving Turing Machine freeze up Word.

Explanation

The Professional button makes the Autocorrect sweep from left to right, running the production rules. On initial state $$, it sees a $ in the first position and replaces it with $$.

1. Then check the next position to the right.
2. Replace $ with $$, otherwise halt.
3. Repeat.

Note: the GUI doesn't show the $'s being generated as the GUI doesn't update until the operation halts, which it won't here. If you open up your Task Manager, you can see the memory usage going up to see that this is indeed what's happening. Sure, I could have made it produce more $s but the production rate would still just be O(1) per loop anyway, and I'd be spending precious bytes programming it. Oh, and I'm counting the $s as output.

Answer 14

Brachylog, 2 bytes

ẉ⊥

Try it online!

Not only does it print infinitely, this prints something much more interesting than most answers here: all integers.

Explanation

        Assign an integer value to the input ; since it is not constrained, it can take any
          value in (-∞, +∞), meaning there is an infinite number of choice points
        The way = is implemented makes it so that the order of choices it will try is:
          0, 1, -1, 2, -2, 3, -3, …
         
 ẉ      Write that integer to STDOUT, followed by a linebreak
  ⊥     False (i.e. go back and try the next integer choice point)

Answer 15

tinylisp, 15 bytes

(d f(q(A(f g
(f

Try it online!

An infinite stream of errors. Just as DLosc intended, hopefully.

Answer 16

Haskell, 18 chars

a=1:a;main=print a

N.B.: No new line at end!

Answer 17

Perl, 10 chars

TIMTOWTDI:

$ perl -nE 'say;redo' <input>   # 10 chars (1+8+1)
$ perl -E 'say while+1'         # 11 chars
$ perl -E 'o:say;goto o'        # 12 chars
$ perl -E 'for(;;){say}'        # 12 chars
$ cat inf.pl
warn;exec$^X,$0                 # 15 chars

If you have infinite RAM (maybe in the cloud ;-)

$ perl -E 'sub o{say;&o}o'      # 14 chars
$ perl -E '&{*1=sub{say;&1}}'   # 17 chars, just kidding *gg*

Answer 18

Matlab, 13

while 1
1
end

This prints

ans =

 1

infinitely many times.

Answer 19

Emotinomicon 18 bytes, 5 chars

😀⏪😀😨⏩

Explanation:

😀 - push 0 to the stack
⏪ - open loop
😀 - push 0 to the stack
😨 - pop top of the stack, and output it as a number
⏩ - end loop

As long as there's something on the stack, it's going to loop indefinitely

Answer 20

PHP - 17 16 13 11 bytes

<?for(;;)echo O;

Oh well, I guess PHP can't ever always win... _{Thank you, m.buettner}

Edit:

<?for(;;)0/0;

As it turns out, division by zero triggers a warning in php. So, even though the output it produces goes to STDERR, it's still infinite!

Edit 2:

for(;;)0/0;

(Run with php -r)

Answer 21

Wolfram Language ( Mathematica ) 14 bytes 12 characters

Do[Echo@1,∞]

Answer 22

unsure, 20 bytes

um but uh okay wait

Don't try it online, it freezes the browser. Listen to the code. Even it wants you to wait. Think this through. Don't be like me. Don't lose that unsaved tab.

Answer 23

tinylisp, 13 bytes

(d f(q(a(f
(f

Try it online!

Outputs an infinite stream of errors. -1 thanks to DLosc.

The tinylisp interpreter throws a warning because a shadows the builtin a, but continues evaluation.

Answer 24

Bash, 3 bytes

top

Haven't seen anyone do this yet. It's tied with the yes answer.

Answer 25

APL, 7

{∇⎕←⍵}1

Defines a function which output its argument and call itself with the same argument, then call it once with argument 1

Answer 26

Brainfuck, 8 bytes

+[[+.]+]

Assumes wrapping.

I'm aware that a solution was already posted by @cardboard_box - allthough his doesn't print any printable characters.

Answer 27

Shell, 16 Chars

cat /dev/urandom

Answer 28

Haskell, 9 characters

show[1..]

Prints an infinite list of integers starting from 1, exploiting the lazy evaluation of Haskell.

Answer 29

Piet, 3 codels

==> <== here it is ;)

Just to make it visible, the same at codel size 10:

This program bounces forward and backward, executing:

forward direction:

1
PSH (push on stack)
OUN (output number)

backward direction:

MUL (multiply)
POP (pop from stack)

The backward instructions are ignored because the stack is empty.

So, the program prints an infinite amount of 1’s in the console.

Edit: I just noticed that captncraig came up with the same answer before me. Sorry for that. Please upvote captncraig’s answer instead.

Answer 30

ArnoldC, 81 bytes

IT'S SHOWTIME
STICK AROUND 1
TALK TO THE HAND 0
CHILL
YOU HAVE BEEN TERMINATED

Prints 0 forever.

Explanation

IT'S SHOWTIME            # start program
STICK AROUND 1           # infinite while loop (since 1!=0)
TALK TO THE HAND 0       # print 0
CHILL                    # end loop
YOU HAVE BEEN TERMINATED # end program