Shortest non-null bash quine

Question

The shortest bash quine is the null string:

$ bash -c ''
$

What is the shortest non-null bash script which produces its own source code as output?

score 7 · Accepted Answer · answered Dec 02 '16 at 13:21

7

19 characters:

$echo 'echo $BASH_COMMAND' > quine
$ wc -c quine
19 quine
$ cat quine
echo $BASH_COMMAND
$ bash quine
echo $BASH_COMMAND
$

The character count includes the newline in the source (because it is produced in the output).

If you've not heard of $BASH_COMMAND before, the manual says:

BASH_COMMAND

The command currently being executed or about to be executed, unless the shell is executing a command as the result of a trap, in which case it is the command executing at the time of the trap.

answered Dec 02 '16 at 13:21

Tom Hale

40,825
36
187
242

I thought I had discovered a new shortest, as the [shortest quines list](http://codegolf.stackexchange.com/q/69/58256) currently says `Bash - 20 by LinusKrom`, but LinusKrom also gives this same 19 character solution [here](http://codegolf.stackexchange.com/a/96563/58256). – Tom Hale Dec 02 '16 at 13:34

score 0 · Answer 2 · answered Dec 18 '19 at 15:24

0

I feel like:

cat $0

should work but they dont accept it

answered Dec 18 '19 at 15:24

grand central

49
4

this is a hole in code golf named "quine". the comment on the accepted solution references it – grand central Dec 18 '19 at 15:36

score 0 · Answer 3 · answered Apr 20 '22 at 04:28

I think I just stumbled on a bash quine, which may be the shortest non-empty one, though cheating a little bit:

you write a file like this:

#!/bin/cat

do chmod a+x on the file

then do ./file

the output will produce the contents of the file itself lol

Shortest non-null bash quine

3 Answers3