Quine generator

[Anonymous Monk]

Not exactly on obfuscation, but I didn't know where else to put it... Warning: neither __END__ nor @data can be used anywhere in the programs in question, lest it will fail.

#!/usr/bin/perl
use strict;
use warnings;

die("File does not exist.\n") unless -e $ARGV[0];

open(QUINE, "+<", shift);
my @quine = <QUINE>;

push @quine,
  'my @data = <DATA>;'."\n",
  'print @data, @data'."\n",
  "__END__\n";
push @quine, @quine;

seek(QUINE, 0, 0);
print QUINE @quine;
close(QUINE);
my @data = <DATA>;
print @data, @data
__END__
#!/usr/bin/perl
use strict;
use warnings;

die("File does not exist.\n") unless -e $ARGV[0];
open(QUINE, "+<", shift);
my @quine = <QUINE>;

push @quine, 
  'my @data = <DATA>;'."\n",
  'print @data, @data'."\n",
  "__END__\n";
push @quine, @quine;

seek(QUINE, 0, 0);
print QUINE @quine;
close(QUINE);
my @data = <DATA>;
print @data, @data
__END__

[shmem]

This one from Dave Mitchell is particularly nice: Punctuation free quine

s zzs vvxv
and s ZVZchr 122Zie
and s ZVZchr 122Zie
and s ZVZchr 122Zie
and s SxSlcfirstSe
and s YZZxZYvvxvYi and print
z
and s ZVZchr 122Zie
and s ZVZchr 122Zie
and s ZVZchr 122Zie
and s SxSlcfirstSe
and s YZZxZYvvxvYi and print

[mtve]

classical one was:

open 0;print<0>

[ambrus]

Classical ones are on the Quine page (which is apparently not maintained anymore).

The shortest non-empty non-cheating one I know is (ends with two newlines)

print<< x2,v10
print<< x2,v10

Another that uses perl's various quoting operators to avoid having to escape stuff dynamically is (no newline)

$a=q(;print"\$a=q($a)$a");print"\$a=q($a)$a"

Update: see Short quines.

[Anonymous Monk]

That's CHEATING!!!!

[Zaxo]

I once twisted the rules to produce a quine generator which would work on programs that print to STDOUT. The twist was that the "own source print" happened on STDERR. That was at Quine code with quinify. It came out of an attempt to quine some of Erudil's famous obfus.