obfuscation, golfing and secret operators in perl
Post on 15-Jan-2015
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OGSOPObfuscation, Golfing and Secret Operators in Perl
難読化・Perl Golf・ひみつの演算子
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Obfuscation難読化
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How do I impress my friends who don’t know much Perl
with obfuscation?
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With simple things
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#!/usr/bin/perl $:?do{exit&&exit}:print"Just another Perl hacker,"
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#!/usr/bin/perl $:?do{exit||exit}:print"Just another Perl hacker,"
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Spaces? What spaces?
$:?do{exit&&exit}:print"Just another Perl hacker,"
スペース？ どれよ？
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#!/usr/bin/perl$:? do {exit &&exit } : print“Just another”.“ Perl hacker,”
Use newlines...
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#!/usr/bin/perl$:?do{exit&&exit }:print“Jus”.“t a”.“not”.“her”.“ Pe”.“rl “.“hac”.“ker,”
As many as you can...
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if($var) {$var = 0 }else {$var = 1 }
Forget about indentation
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if($var) {$var = 0 } else {$var = 1 }
Or at least use it wrongly
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print "Hello " ;print "World"
Semicolons: use wrongly
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;;;;;;;;;;;;;;;;;;;;;;;;;print "Hello World";;;;;;;;;;;;;;;;;;;;;;;;;
;;s;;print "Hello World";e;;
Semicolons: use plenty
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$a++ ; $b--$a++ , $b--$a++ . $b--$a++ .. $b--
Semicolons: use alternatives
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s//Just another Perl hacker,/ ; print
Use things indirectly
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Bend the rules
s/ / /;y/ / /;
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Bend the rules
s; ; ; ;s { }[ ]s s s sy ; ; ;;y y y y
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And use unneeded things
; s ; ; ; ;{ };s{ }[ ]s s s s s; y ; ; ; ;
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Mix them together
y s y s y ss y s y s y
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Mix things up
1?s::::0
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Mix things up
1 ? s::: : 0
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Is it code?
y//No, it is not/;
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Is it a comment?
s##No, it is not#;
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Is it a comment?
s##we want to print "Just another Perl hacker,"##
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Is it a comment?
s;;;;s ##we want to print "Just another Perl hacker,"##
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Is it a comment?
s;;;;s##we want to print "Just another Perl hacker,"##
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Is it a comment?
s;old;new;g;s##we want to print "Just another Perl hacker,"##
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Is it a comment?
s;old;new;g;s##we want to print "Just another Perl hacker,"##;s^.{11}^^&&eval;
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Are those brackets closed?
{y/}/{/}
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WYSINWYG
$ perl -le ‘print “All digits!” if 0x20 =~ /^\d+\z/’All digits!
$ perl -le ‘print 0x2032
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WYSINWYG
print "No underscores!" if 1_234_567_890 !~ /_/; print "No e!" if 1e6 !~ /e/; print "There is an e!" if 6666666666666666 =~ /e/; print "There is a plus!" if 1e15 =~ /\+/; print "No dot!" if 0.00 !~ /\./;
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Hexadecimal or... whatever
eval "\x70\x72\x69\x6e\x74";
eval "\160\x72\151\x6e\164";
$_="0741171151160320971101111161041011140320801011". "14108032104097099107101114046";s;...;print chr$&;eg
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$;$:$_$^@^
Variable names
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$ ;$ :$ _$ ^@ ^
Variable names: and behold
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1 ? s : $ s : : : 0
Variable names: mix them
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1 ? s : s $ s : s $ s : : 0
Variable names: cleverly
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print ${1+1}
Variable names: calculate
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print ${$_}
Variable names: store them
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@_=(Just,another,Perl,hacker);$,=$”;print@_
$,=” another Perl “;print(“Just”,”hacker”);
Special variables
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y/a-z/:-z/
Behind human capabilities
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|&^~
Use uncommon things
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print “a” | “c”;print ~0 & 2 ;print 1 ^ 2 ;print ~0;
Use uncommon things
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sub _ { “something tricky” }_$_
so you can do clever things
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$_ = sub _ { “something tricky” }&{$_}
or don’t name it at all
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s;;;
And be inventive
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;;;;s;;;;
And be *very* inventive
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g;;;s;;;g
And be *VERY* inventive
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Example例
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print "Just another Perl hacker,"
JAPH
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print "Just ", "another ", "Perl ", "hacker,"
JAPH
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$, = " ";print "Just", "another", "Perl", "hacker,"
JAPH
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$, = " "; print reverse "hacker,", "Perl", "another", "Just"
JAPH
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$, = " "; print reverse"hacker,","Perl","another","Just"
JAPH
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$, = " "; push@,,$_ for reverse"hacker,","Perl","another",”Just”;
print @_
JAPH
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$, = $" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;
print @_
JAPH
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$, =+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;
print @_
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;
print @_
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”; join$,,@_ ;print $_
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s //join$,,@_/e;print $_
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s //”join”.’$,,@_’/ee;print $_
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s //"\x6a\x6f\x69\x6e".’$,,@_’/ee;print $_
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s //"\x6a\x6f\x69\x6e".’$,,@,’/ee;print $_
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s //"\x6a\x6f\x69\x6e".’$,,@,’/ee;print
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s{}/"\x6a\x6f\x69\x6e".’$,,@,’/ee;print
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s{};"\x6a\x6f\x69\x6e".’$,,@,’;ee;print
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s{};"print \x6a\x6f\x69\x6e".’$,,@,’;ee;eval
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s{};"print \x6a\x6f\x69\x6e".’$,,@,’;eee
JAPH
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+$,=+$" ; push@,,$_ for reverse"hacker,","Perl","another",”Just”;s{};"\160\162\151\156\164 \x6a\x6f\x69\x6e".’$,,@,’;eee
JAPH
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(+$,=+$"). push@,,$_ for reverse"hacker,","Perl","another",”Just”;s{};"\160\162\151\156\164 \x6a\x6f\x69\x6e".’$,,@,’;eee
JAPH
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(+$,=+$").#s# most people # think # this is a comment #push@,,$_ for reverse"hacker,","Perl","another",”Just”;s{};"\160\162\151\156\164 \x6a\x6f\x69\x6e".’$,,@,’;eee
JAPH
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Warning警告
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Don’t you ever, ever, ever, run obfuscated code you don’t
understand and cannot trust
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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$??s:;s:s;;$?::s;;=]=>%-{<-|}<&|‘{; ; y; -/:-@[-‘{-};‘-{/" -;;s;;$_;see
Random code on the web
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So what’s on $_ afterall?
Random code on the web
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So what’s on $_ afterall?
system”rm -rf /”
Random code on the web
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Golfingゴルフ
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One character variables
$c $d $e $f $g
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If you don’t need it...
print “something”;
print”something”
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Forget about \n
s/\n//;
s///;
$_=”something\n”
$_=”something“
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END in the beginning
something;END{something_else}
END{something_else}something
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Learn the alternatives
map{[$_]}@array
map[$_],@array
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for the other way around
for(@a){something}
something for@a
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Learn the switches
#!/usr/bin/perlprint”this\n”;print”that\n”;print”the other\n”;
#!/usr/bin/perl -lprint”this”;print”that”;print”the other”;
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Learn the special variables
#!/usr/bin/perl@_=qw/Just another Perl hacker,/;print join” “,@_
#!/usr/bin/perl@_=qw/Just another Perl hacker,”;print”@_”
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Golfing techniques
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Golfing techniques
$_ x=
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Golfing techniques
What does this do?
$_ x= / /;
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Golfing techniques
y///c
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Secret Operatorsひみつの演算子
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Secret Eskimo Greeting
}{
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Secret Eskimo Greeting
#!/usr/bin/perl -n# What does this do?}{print$.
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Secret Eskimo Greeting
$ perldoc -perlrun
[...]
#!/usr/bin/perlLINE: while (<>) { ... # your program goes here }
[...]
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Secret Eskimo Greeting
#!/usr/bin/perlLINE: while (<>) {}{print$. }
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Supermarket Trolley
@{[]}
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Supermarket Trolley
my @stuff = qw/pocket_watch 3ninja_tshirts/;
print "Our list includes: @{[map {ucfirst} @things_for_my_other_talks]}."
print "Our list includes: ", map {ucfirst} @things_for_my_other_talks], "."
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Supermarket Trolley
my @stuff = qw/pocket_watch 3ninja_tshirts/;
print "Our list includes: @{[map {ucfirst} @things_for_my_other_talks]}."
print "Our list includes: ", map {ucfirst} @things_for_my_other_talks], "."
my @new_list = map {ucfirst} @things_for_my_other_talks;
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Supermarket Trolley
my @stuff = qw/pocket_watch 3ninja_tshirts/;
print "Our list includes: @{[map {ucfirst} @things_for_my_other_talks]}."
print "Our list includes: ", map {ucfirst} @things_for_my_other_talks], "."
my @new_list = map {ucfirst} @things_for_my_other_talks;
print "Our list includes: @new_list."
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Goatse
=()=
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Goatse
my $_ = "Just another Perl hacker,";my $spaces =()= / /g
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Inchworm on a stick
~-
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Inchworm on a stick
What does this do?
$y = ~-$x*4;
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Inchworm on a stick
What does this do?
$y = ~-$x*4;$y = ($x-1)*4;
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Inchworm on a stick
What does this do?
$y = ~-$x*4;$y = ($x-1)*4;
High precedence decrement
(or a high precedence increment, if $x<0)
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///
///
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///
What does this do?
print ///4;
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///
What does this do?
print ///4;print //; # prints 1
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///
What does this do?
print ///4;print //; # prints 1print 1/4; # prints 0.25
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///
What does this do?
print ///4;print //; # prints 1print 1/4; # prints 0.25print ///4; # prints 0.25
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Inchworm
~~
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Inchworm
What does this do?
print ~~ gmtime
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Inchworm
$ perl -e 'print gmtime'31441214410831340
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Inchworm
$ perl -e 'print gmtime'31441214410831340
$ perl -e 'print ~~ gmtime'Wed May 14 12:44:35 2008
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Min Max
[ ]->[ ]
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Min Max
What does this do?
[ $x => $y ]->[ $y <= $x ]
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Min Max
What does this do?
[ $x => $y ]->[ $y <= $x ]
...that’s the lesser of $x and $y
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Min Max
What does this do?
[ $x => $y ]->[ $y <= $x ]
...that’s the lesser of $x and $y
[ $x => $y ]->[ $x <= $y ]
...and that’s the greater of $x and $y
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Examples例
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Erudil’s Camel Code #!/usr/bin/perl -w # camel codeuse strict;
$_='ev al("seek\040D ATA,0, 0;");foreach(1..3) {<DATA>;}my @camel1hump;my$camel; my$Camel ;while( <DATA>){$_=sprintf("%-69s",$_);my@dromedary 1=split(//);if(defined($_=<DATA>)){@camel1hum p=split(//);}while(@dromeda ry1){my$camel1hump=0 ;my$CAMEL=3;if(defined($_=shif t(@dromedary1 ))&&/\S/){$camel1hump+=1<<$CAMEL;} $CAMEL--;if(d efined($_=shift(@dromedary1))&&/\S/){ $camel1hump+=1 <<$CAMEL;}$CAMEL--;if(defined($_=shift( @camel1hump))&&/\S/){$camel1hump+=1<<$CAMEL;}$CAMEL--;if( defined($_=shift(@camel1hump))&&/\S/){$camel1hump+=1<<$CAME L;;}$camel.=(split(//,"\040..m`{/J\047\134}L^7FX"))[$camel1h ump];}$camel.="\n";}@camel1hump=split(/\n/,$camel);foreach(@ camel1hump){chomp;$Camel=$_;y/LJF7\173\175`\047/\061\062\063\ 064\065\066\067\070/;y/12345678/JL7F\175\173\047`/;$_=reverse; print"$_\040$Camel\n";}foreach(@camel1hump){chomp;$Camel=$_;y /LJF7\173\175`\047/12345678/;y/12345678/JL7F\175\173\0 47`/; $_=reverse;print"\040$_$Camel\n";}';;s/\s*//g;;eval; eval ("seek\040DATA,0,0;");undef$/;$_=<DATA>;s/\s*//g;( );;s ;^.*_;;;map{eval"print\"$_\"";}/.{4}/g; __DATA__ \124 \1 50\145\040\165\163\145\040\157\1 46\040\1 41\0 40\143\141 \155\145\1 54\040\1 51\155\ 141 \147\145\0 40\151\156 \040\141 \163\16 3\ 157\143\ 151\141\16 4\151\1 57\156 \040\167 \151\164\1 50\040\ 120\1 45\162\ 154\040\15 1\163\ 040\14 1\040\1 64\162\1 41\144 \145\ 155\14 1\162\ 153\04 0\157 \146\ 040\11 7\047\ 122\1 45\15 1\154\1 54\171 \040 \046\ 012\101\16 3\16 3\15 7\143\15 1\14 1\16 4\145\163 \054 \040 \111\156\14 3\056 \040\ 125\163\145\14 4\040\ 167\1 51\164\1 50\0 40\160\ 145\162 \155\151 \163\163 \151\1 57\156\056
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Saturn
#!/usr/bin/perl ;;;;;; ;;;;;;;;;;; ;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;; +$I=sub{+s+^+ ;;;;;;; ;;;;;;;;; $"x$_[1]+gem;$/x$_# ;;;; ;;;;;;;; [0].$_.$/};$W=sub{$~=!q~ ;;;;;;; ~.pop();system($^O=~Win?ClS:# ;;;;;;; 'clear'),print,select$Z,$Z,$Z,!" ;;;;;; "||$~for@_};$H=sub{+join$/,map($_# ;;;;;; x$_[0],pop=~m-.+-g),!_};$_=!Mima,s-- ;;;;; "@{['=9+)w'^RINGS]}\%;local@{[Saturn^# ;;;;; wNXIBP]}"-see;s-^#!..+?$/(?=$"+;)--is ;;;; y-;-'-;s-\w-~-gi;$S=$_;#--Beautiful] ;;;; @S=m-.+-g;$N=1+.6-!th_,$--=-82-$--- ;;; $_.=$"x-(y---c-$-)for@S;$R=sub{$i# ;;; -d =0;join$/,map{$j=$%;join!_,grep# ;;; Rhea !($j++%$_[$%]),m-.-g}grep!($i# ;;; -Titan ++%$_[0]),@S};$L=join!_,map# ;;; -Huygens ~~reverse.$/,@S;@R=(&$I(q- ;;; -&&20,051, $_=_^q-q-),&$I(20,41-!q- ;;; -,$_=F|K),$ I->(15,31,$_=&$R(4-!q- ;;; -)),&$I(13-!" ;;",28,$_=&$R(3)),&${ ;;; _^_^I}(10,20-!" ;;;;;",$_=$R->(2)),q- ;;; -&&$S);@O=map&{" ;;;;;; "&&$H}($_,&${ ;;; R.!-_}($_))x$_,!" ;;;;; "+2..2*~~2 ;;; @Y=reverse@R#Dione ;;;;;; &${m-- ;;; S|A|T|U}(@R,$N)||!q- ;;;;;;; b- ;;; &$W(@O[0,1,2,1,0!=!q- ;;;;;;; ;;;; -],!1!~~1);&$W($S.!q- ;;;;;;;;; ;;;;; -,$L,0.16)for$%..5+!q- ;;;;;;;;;; ;;;;;;;;; Cassini-;&{$W||q- ;;;;;;;;;;;;;;;;;;;;;; -}(@Y,1.6) ;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;
133
Space Invaders
#!/usr/bin/perl
use strict; use Term'ReadKey;ReadMode 'cbreak';$,=$/;$/=++$b+$b;$=='8';$b=$= x28;$*=$=x2;@!=(qw(4 _ " a 1 1 0 0 ));$![7]=`clear`;push(@!,split shift(@!),q 7$=W8W$=8$b eq "j"8W$=8$=W8 $b eq"l"8W$=8W!8($b eq"k"&&$_!~/!/)a#W$=8#$=W8$=W#8W$=#8#!8##a\*8$=8p$=8$=p 8$=q8q$=8p(#.{59})$=8$=$ 1q8#q(.{60})$=8#$=$1 pap(.{60})!8$![0]++;"\*$ 1$="8q(.{60})!8$![0] ++;"\*$1$="8(t.*)!8$b=(l ength$1)-61;substr($ 1,0,$b )."!". substr($1, $b+1).$=4x"gs'"x"c"es'"c"z"gs if'.shift"z"l"just another perl hacker"l4'SpaceInvaders'.($=x12).'domm@zsi.at j=left k=fire l=right'_'#'x58_("$*p$*"x11).$=x3_$*.("$*$*q"x11).$=_("p$*$*"x11).$=x3_($=x3).("$*$*q"x11)_1_$b.$=."W$b"_'#'x 587);j(split shift@!,pop@!);a(split shift@!,pop@!);push(@!,split shift@!,pop@!);$_=$a;map{s/\n//g}@!;map{s/v//g}@!;map{s/ //g}@!;&p;sub'j{$_=shift;$a.=m/^1/?("#$b$=$=$b#$,"x12):"#".eval( )."#$,";@_&&j(@_)}sub'END{ReadMode 'normal' }sub'a{eval"sub'".pop().'{eval\'s/\'.(shift).\'/\'.(shift).\'/'.pop().';@_&&'.pop().'(@_)}';@_&&a(@_)}sub'p{$b=ReadKey -1;$![1]%3==0&&x(split$=,$![6]);z(split$=,$![4]);x(split$=,$![5]);c(split$=,$![7]);$![1]++;select+(@-,@-,@-,0.05);($![2]=$_)=~s/$=/ /g;/pW|Wq/&&h('Game over');$_!~/p|q/&&h('You saved our planet. Yeah');print$![3],$![2 ];&p}sub h{print $![ 3],shift,"You killed $![0] space invaders ",$,;exit}
134
See alsoも参照ください
135
• The Art of Obfuscation, by Thomas Klausner
• How to Write Unmaintainable Code, by Roedy Green
136
Thank you
137
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