Thank you for this.

This is the message I got:

syntax error at ns.pl line 1, near "-le"
Execution of ns.pl aborted due to compilation errors.
[download]

The solution I posted is a one-line perl command, to be run from a command shell prompt, not to be embedded within a perl source file.

If you're running under *nix, then you'll have to exchange the quotes like so:

perl -le'%h=(), undef @h{split"",$_}, keys %h == 3 and print for "0000
+".."9999"'
[download]

The following will run as a script:

#!/usr/bin/perl -lw
use strict;

for ( '0000'..'9999' ) {
    my %h;
    undef @h{split'',$_};
    keys %h == 3 and print;
}
[download]

---

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

"I'd rather go naked than blow up my ass"

Thank you sir - that did it :)
Hooray . . . now on to the next step of my Evil Masterplan ;-)

Cheers,
M.ROMAN

perldoc perlrun

$ perl -MO=Deparse   -le"%h=(), undef @h{split'',$_}, keys %h == 3 and
+ print for '0000'..'9999'"
BEGIN { $/ = "\n"; $\ = "\n"; }
;
(%h) = (), undef @h{split(//, $_, 0)}, keys %h == 3 and print $_ forea
+ch ('0000' .. '9999');
-e syntax OK
[download]

$ indicates a command prompt (a shell, like bash/csh/cmd...)

Anonymous Monk,

Thank you for this. I did as you kindly suggested and here is what happened:

mrh@workstationmachine:~$ BEGIN { $/ = "\n"; $\ = "\n"; }
bash: syntax error near unexpected token `}'
mrh@workstationmachine:~$ ;
bash: syntax error near unexpected token `;'
mrh@workstationmachine:~$ (%h) = (), undef @h{split(//, $_, 0)}, keys 
+%h == 3 and print $_ forea
bash: syntax error near unexpected token `='
mrh@workstationmachine:~$ +ch ('0000' .. '9999');
bash: syntax error near unexpected token `'0000''
mrh@workstationmachine:~$ -e syntax OK
bash: -e: command not found
[download]

?