|Revision 1.23||27 Oct 2003||esr|
If you are reading a snapshot of this document offline, the current version lives at http://catb.org/~esr/faqs/hacker-howto.html.
Note: there is a list of Frequently Asked Questions at the end of this document. Please read thesetwicebefore mailing me any questions about this document.
Numerous translations of this document are available: Bulgarian, Catalan, Chinese (Simplified), Danish, Dutch, FinnishGerman, Hebrew, Hungarian, ItalianJapanese, Korean, Polish, Portuguese (European), Spanish, and Swedish. Note that since this document changes occasionally, they may be out of date to varying degrees.
The five-dots-in-nine-squares diagram that decorates this document is called a glider. It is a simple pattern with some surprising properties in a mathematical simulation called Life that has fascinated hackers for many years. I think it makes a good visual emblem for what hackers are like abstract, at first a bit mysterious-seeming, but a gateway to a whole world with an intricate logic of its own. Read more about the glider emblem here.
There is a community, a shared culture, of expert programmers and networking wizards that traces its history back through decades to the first time-sharing minicomputers and the earliest ARPAnet experiments. The members of this culture originated the term `hacker'. Hackers built the Internet. Hackers made the Unix operating system what it is today. Hackers run Usenet. Hackers make the World Wide Web work. If you are part of this culture, if you have contributed to it and other people in it know who you are and call you a hacker, you're a hacker.
The hacker mind-set is not confined to this software-hacker culture. There are people who apply the hacker attitude to other things, like electronics or music actually, you can find it at the highest levels of any science or art. Software hackers recognize these kindred spirits elsewhere and may call them "hackers" too and some claim that the hacker nature is really independent of the particular medium the hacker works in. But in the rest of this document we will focus on the skills and attitudes of software hackers, and the traditions of the shared culture that originated the term `hacker'.
There is another group of people who loudly call themselves hackers, but aren't. These are people (mainly adolescent males) who get a kick out of breaking into computers and phreaking the phone system. Real hackers call these people `crackers' and want nothing to do with them. Real hackers mostly think crackers are lazy, irresponsible, and not very bright, and object that being able to break security doesn't make you a hacker any more than being able to hotwire cars makes you an automotive engineer. Unfortunately, many journalists and writers have been fooled into using the word `hacker' to describe crackers; this irritates real hackers no end.
The basic difference is this: hackers build things, crackers break them.
If you want to be a hacker, keep reading. If you want to be a cracker, go read the alt.2600 newsgroup and get ready to do five to ten in the slammer after finding out you aren't as smart as you think you are. And that's all I'm going to say about crackers.
But if you think of cultivating hacker attitudes as just a way to gain acceptance in the culture, you'll miss the point. Becoming the kind of person who believes these things is important foryou for helping you learn and keeping you motivated. As with all creative arts, the most effective way to become a master is to imitate the mind-set of masters not just intellectually but emotionally as well.
Or, as the following modern Zen poem has it:
If you aren't the kind of person that feels this way naturally, you'll need to become one in order to make it as a hacker. Otherwise you'll find your hacking energy is sapped by distractions like sex, money, and social approval.
(You also have to develop a kind of faith in your own learning capacity a belief that even though you may not know all of what you need to solve a problem, if you tackle just a piece of it and learn from that, you'll learn enough to solve the next piece and so on, until you're done.)
To behave like a hacker, you have to believe that the thinking time of other hackers is precious so much so that it's almost a moral duty for you to share information, solve problems and then give the solutions away just so other hackers can solve new problems instead of having to perpetually re-address old ones.
(You don't have to believe that you're obligated to giveall your creative product away, though the hackers that do are the ones that get most respect from other hackers. It's consistent with hacker values to sell enough of it to keep you in food and rent and computers. It's fine to use your hacking skills to support a family or even get rich, as long as you don't forget your loyalty to your art and your fellow hackers while doing it.)
To behave like a hacker, you have to believe this enough to want to automate away the boring bits as much as possible, not just for yourself but for everybody else (especially other hackers).
(There is one apparent exception to this. Hackers will sometimes do things that may seem repetitive or boring to an observer as a mind-clearing exercise, or in order to acquire a skill or have some particular kind of experience you can't have otherwise. But this is by choice nobody who can think should ever be forced into a situation that bores them.)
(This isn't the same as fighting all authority. Children need to be guided and criminals restrained. A hacker may agree to accept some kinds of authority in order to get something he wants more than the time he spends following orders. But that's a limited, conscious bargain; the kind of personal surrender authoritarians want is not on offer.)
Authoritarians thrive on censorship and secrecy. And they distrust voluntary cooperation and information-sharing they only like `cooperation' that they control. So to behave like a hacker, you have to develop an instinctive hostility to censorship, secrecy, and the use of force or deception to compel responsible adults. And you have to be willing to act on that belief.
Therefore, you have to learn to distrust attitude and respect competence of every kind. Hackers won't let posers waste their time, but they worship competence especially competence at hacking, but competence at anything is good. Competence at demanding skills that few can master is especially good, and competence at demanding skills that involve mental acuteness, craft, and concentration is best.
If you revere competence, you'll enjoy developing it in yourself the hard work and dedication will become a kind of intense play rather than drudgery. That attitude is vital to becoming a hacker.
This toolkit changes slowly over time as technology creates new skills and makes old ones obsolete. For example, it used to include programming in machine language, and didn't until recently involve HTML. But right now it pretty clearly includes the following:
Java is also a good language for learning to program in. It is more difficult than Python, but produces faster code than Python. I think it makes an excellent second language.
But be aware that you won't reach the skill level of a hacker or even merely a programmer if you only know one or two languages you need to learn how to think about programming problems in a general way, independent of any one language. To be a real hacker, you need to get to the point where you can learn a new language in days by relating what's in the manual to what you already know. This means you should learn several very different languages.
If you get into serious programming, you will have to learn C, the core language of Unix. C++ is very closely related to C; if you know one, learning the other will not be difficult. Neither language is a good one to try learning as your first, however. And, actually, the more you can avoid programming in C the more productive you will be.
C is very efficient, and very sparing of your machine's resources. Unfortunately, C gets that efficiency by requiring you to do a lot of low-level management of resources (like memory) by hand. All that low-level code is complex and bug-prone, and will soak up huge amounts of your time on debugging. With today's machines as powerful as they are, this is usually a bad tradeoff it's smarter to use a language that uses the machine's time less efficiently, but your time much more efficiently. Thus, Python.
Other languages of particular importance to hackers include Perl and LISP. Perl is worth learning for practical reasons; it's very widely used for active web pages and system administration, so that even if you never write Perl you should learn to read it. Many people use Perl in the way I suggest you should use Python, to avoid C programming on jobs that don't require C's machine efficiency. You will need to be able to understand their code.
LISP is worth learning for a different reason the profound enlightenment experience you will have when you finally get it. That experience will make you a better programmer for the rest of your days, even if you never actually use LISP itself a lot. (You can get some beginning experience with LISP fairly easily by writing and modifying editing modes for the Emacs text editor.)
It's best, actually, to learn all five of these (Python, Java, C/C++, Perl, and LISP). Besides being the most important hacking languages, they represent very different approaches to programming, and each will educate you in valuable ways.
I can't give complete instructions on how to learn to program here it's a complex skill. But I can tell you that books and courses won't do it (many, maybe most of the best hackers are self-taught). You can learn language features bits of knowledge from books, but the mind-set that makes that knowledge into living skill can be learned only by practice and apprenticeship. What will do it is (a) reading code and (b)writing code.
Learning to program is like learning to write good natural language. The best way to do it is to read some stuff written by masters of the form, write some things yourself, read a lot more, write a little more, read a lot more, write some more ... and repeat until your writing begins to develop the kind of strength and economy you see in your models.
Finding good code to read used to be hard, because there were few large programs available in source for fledgeling hackers to read and tinker with. This has changed dramatically; open-source software, programming tools, and operating systems (all built by hackers) are now widely available. Which brings me neatly to our next topic...
Yes, there are other operating systems in the world besides Unix. But they're distributed in binary you can't read the code, and you can't modify it. Trying to learn to hack on a Windows machine or under MacOS or any other closed-source system is like trying to learn to dance while wearing a body cast.
Under OS/X it's possible, but only part of the system is open source you're likely to hit a lot of walls, and you have to be careful not to develop the bad habit of depending on Apple's proprietary code. If you concentrate on the Unix under the hood you can learn some useful things.
Unix is the operating system of the Internet. While you can learn to use the Internet without knowing Unix, you can't be an Internet hacker without understanding Unix. For this reason, the hacker culture today is pretty strongly Unix-centered. (This wasn't always true, and some old-time hackers still aren't happy about it, but the symbiosis between Unix and the Internet has become strong enough that even Microsoft's muscle doesn't seem able to seriously dent it.)
So, bring up a Unix I like Linux myself but there are other ways (and yes, you can run both Linux and Windows on the same machine). Learn it. Run it. Tinker with it. Talk to the Internet with it. Read the code. Modify the code. You'll get better programming tools (including C, LISP, Python, and Perl) than any Microsoft operating system can dream of hosting, you'll have fun, and you'll soak up more knowledge than you realize you're learning until you look back on it as a master hacker.
To get your hands on a Linux, see the Linux Online! site; you can download from there or (better idea) find a local Linux user group to help you with installation. From a new user's point of view, all Linux distributions are pretty much equivalent.
You can find BSD Unix help and resources at www.bsd.org.
I have written a primer on the basics of Unix and the Internet.
(Note: I don't really recommend installing either Linux or BSD as a solo project if you're a newbie. For Linux, find a local Linux user's group and ask for help.)
This doesn't just mean learning how to drive a browser (anyone can do that), but learning how to write HTML, the Web's markup language. If you don't know how to program, writing HTML will teach you some mental habits that will help you learn. So build a home page. Try to stick to XHTML, which is a cleaner language than classic HTML. (There are good beginner tutorials on the Web; here's one.)
But just having a home page isn't anywhere near good enough to make you a hacker. The Web is full of home pages. Most of them are pointless, zero-content sludge very snazzy-looking sludge, mind you, but sludge all the same (for more on this see The HTML Hell Page).
To be worthwhile, your page must havecontent it must be interesting and/or useful to other hackers. And that brings us to the next topic...
This is very true. Back around 1991 I learned that many hackers who have English as a second language use it in technical discussions even when they share a birth tongue; it was reported to me at the time that English has a richer technical vocabulary than any other language and is therefore simply a better tool for the job. For similar reasons, translations of technical books written in English are often unsatisfactory (when they get done at all).
Linus Torvalds, a Finn, comments his code in English (it apparently never occurred to him to do otherwise). His fluency in English has been an important factor in his ability to recruit a worldwide community of developers for Linux. It's an example worth following.
Accordingly, when you play the hacker game, you learn to keep score primarily by what other hackers think of your skill (this is why you aren't really a hacker until other hackers consistently call you one). This fact is obscured by the image of hacking as solitary work; also by a hacker-cultural taboo (now gradually decaying but still potent) against admitting that ego or external validation are involved in one's motivation at all.
Specifically, hackerdom is what anthropologists call a gift culture. You gain status and reputation in it not by dominating other people, nor by being beautiful, nor by having things other people want, but rather by giving things away. Specifically, by giving away your time, your creativity, and the results of your skill.
There are basically five kinds of things you can do to be respected by hackers:
(We used to call these works ``free software'', but this confused too many people who weren't sure exactly what ``free'' was supposed to mean. Most of us, by at least a 2:1 ratio according to web content analysis, now prefer the term ``open-source'' software).
Hackerdom's most revered demigods are people who have written large, capable programs that met a widespread need and given them away, so that now everyone uses them.
If you're a newbie, try to find a program under development that you're interested in and be a good beta-tester. There's a natural progression from helping test programs to helping debug them to helping modify them. You'll learn a lot this way, and generate good karma with people who will help you later on.
Maintainers of major technical FAQs get almost as much respect as open-source authors.
People who do this sort of thing well get a lot of respect, because everybody knows these jobs are huge time sinks and not as much fun as playing with code. Doing them shows dedication.
The hacker culture doesn't have leaders, exactly, but it does have culture heroes and tribal elders and historians and spokespeople. When you've been in the trenches long enough, you may grow into one of these. Beware: hackers distrust blatant ego in their tribal elders, so visibly reaching for this kind of fame is dangerous. Rather than striving for it, you have to sort of position yourself so it drops in your lap, and then be modest and gracious about your status.
For this reason, many hackers have adopted the label `nerd' and even use the harsher term `geek' as a badge of pride it's a way of declaring their independence from normal social expectations. See The Geek Page for extensive discussion.
If you can manage to concentrate enough on hacking to be good at it and still have a life, that's fine. This is a lot easier today than it was when I was a newbie in the 1970s; mainstream culture is much friendlier to techno-nerds now. There are even growing numbers of people who realize that hackers are often high-quality lover and spouse material.
If you're attracted to hacking because you don't have a life, that's OK too at least you won't have trouble concentrating. Maybe you'll get a life later on.
Read science fiction. Go to science fiction conventions (a good way to meet hackers and proto-hackers).
Study Zen, and/or take up martial arts. (The mental discipline seems similar in important ways.)
Develop an analytical ear for music. Learn to appreciate peculiar kinds of music. Learn to play some musical instrument well, or how to sing.
Develop your appreciation of puns and wordplay.
Work as intensely as you play and play as intensely as you work. For true hackers, the boundaries between "play", "work", "science" and "art" all tend to disappear, or to merge into a high-level creative playfulness. Also, don't be content with a narrow range of skills. Though most hackers self-describe as programmers, they are very likely to be more than competent in several related skills system administration, web design, and PC hardware troubleshooting are common ones. A hacker who's a system administrator, on the other hand, is likely to be quite skilled at script programming and web design. Hackers don't do things by halves; if they invest in a skill at all, they tend to get very good at it.
Don't get in flame wars on Usenet (or anywhere else).
Don't call yourself a `cyberpunk', and don't waste your time on anybody who does.
Don't post or email writing that's full of spelling errors and bad grammar.
The problem with screen names or handles deserves some amplification. Concealing your identity behind a handle is a juvenile and silly behavior characteristic of crackers, warez d00dz, and other lower life forms. Hackers don't do this; they're proud of what they do and want it associated with their real names. So if you have a handle, drop it. In the hacker culture it will only mark you as a loser.
There is a document called How To Be A Programmer that is an excellent complement to this one. It has valuable advice not just about coding and skillsets, but about how to function on a programming team.
I have also written A Brief History Of Hackerdom.
I have written a paper, The Cathedral and the Bazaar, which explains a lot about how the Linux and open-source cultures work. I have addressed this topic even more directly in its sequel Homesteading the Noosphere.
Rick Moen has written an excellent document on how to run a Linux user group.
Rick Moen and I have collaborated on another document on How To Ask Smart Questions. This will help you seek assistance in a way that makes it more likely that you will actually get it.
If you need instruction in the basics of how personal computers, Unix, and the Internet work, see The Unix and Internet Fundamentals HOWTO.
When you release software or write patches for software, try to follow the guidelines in the Software Release Practice HOWTO.
If you enjoyed the Zen poem, you might also like Rootless Root: The Unix Koans of Master Foo.
|Q:.||Will you teach me how to hack?|
|A:.||Since first publishing this page, I've gotten
several requests a week (often several a day) from people to "teach me
all about hacking". Unfortunately, I don't have the time or energy to do
this; my own hacking projects, and traveling as an open-source advocate,
take up 110% of my time.
Even if I did, hacking is an attitude and skill you basically have to teach yourself. You'll find that while real hackers want to help you, they won't respect you if you beg to be spoon-fed everything they know.
Learn a few things first. Show that you're trying, that you're capable of learning on your own. Then go to the hackers you meet with specific questions.
If you do email a hacker asking for advice, here are two things to know up front. First, we've found that people who are lazy or careless in their writing are usually too lazy and careless in their thinking to make good hackers so take care to spell correctly, and use good grammar and punctuation, otherwise you'll probably be ignored. Secondly, don't dare ask for a reply to an ISP account that's different from the account you're sending from; we find people who do that are usually thieves using stolen accounts, and we have no interest in rewarding or assisting thievery.
|Q:.||How can I get started, then?|
|A:.||The best way for you to get started would probably be to go to a LUG (Linux user group) meeting. You can find such groups on the LDP General Linux Information Page; there is probably one near you, possibly associated with a college or university. LUG members will probably give you a Linux if you ask, and will certainly help you install one and get started.|
|Q:.||When do you have to start? Is it too late for me to learn?|
|A:.||Any age at which you are motivated to start is a good age. Most people seem to get interested between ages 15 and 20, but I know of exceptions in both directions.|
|Q:.||How long will it take me to learn to hack?|
|A:.||That depends on how talented you are and how hard you work at it. Most people can acquire a respectable skill set in eighteen months to two years, if they concentrate. Don't think it ends there, though; if you are a real hacker, you will spend the rest of your life learning and perfecting your craft.|
|Q:.||Are Visual Basic or C# good languages to start with?|
|A:.||If you're asking this question, it almost certainly
means you're thinking about trying to hack under Windows. This is a bad
idea in itself. When I compared trying to learn to hack under Windows to
trying to learn to dance while wearing a body cast, I wasn't kidding. Don't
go there. It's ugly, and it never stops being ugly.
There are specific problems with Visual Basic and C#; mainly that they're not portable. Though there are prototype open-source implementations of these languages, the applicable ECMA standards don't cover more than a small set of their programming interfaces. On Windows most of their library support is proprietary to a single vendor (Microsoft); if you aren't extremely careful about which features you use more careful than any newbie is really capable of being you'll end up locked into only those platforms Microsoft chooses to support. If you're starting on a Unix, much better languages with better libraries are available.
Visual Basic is especially awful. Like other Basics it's a poorly-designed language that will teach you bad programming habits. No, don't ask me to describe them in detail; that explanation would fill a book. Learn a well-designed language instead.
One of those bad habits is becoming dependent on a single vendor's libraries, widgets, and development tools. In general, any language that isn't fully supported under at least Linux or one of the BSDs, and/or at least three different vendors' operating systems, is a poor one to learn to hack in.
|Q:.||Would you help me to crack a system, or teach me how to crack?|
|A:.||No. Anyone who can still ask such a question after reading this FAQ is too stupid to be educable even if I had the time for tutoring. Any emailed requests of this kind that I get will be ignored or answered with extreme rudeness.|
|Q:.||How can I get the password for someone else's account?|
|A:.||This is cracking. Go away, idiot.|
|Q:.||How can I break into/read/monitor someone else's email?|
|A:.||This is cracking. Get lost, moron.|
|Q:.||How can I steal channel op privileges on IRC?|
|A:.||This is cracking. Begone, cretin.|
|Q:.||I've been cracked. Will you help me fend off further attacks?|
|A:.||No. Every time I've been asked this question so far, it's been from some poor sap running Microsoft Windows. It is not possible to effectively secure Windows systems against crack attacks; the code and architecture simply have too many flaws, which makes securing Windows like trying to bail out a boat with a sieve. The only reliable prevention starts with switching to Linux or some other operating system that is designed to at least be capable of security.|
|Q:.||I'm having problems with my Windows software. Will you help me?|
|A:.||Yes. Go to a DOS prompt and type "format c:". Any problems you are experiencing will cease within a few minutes.|
|Q:.||Where can I find some real hackers to talk with?|
|A:.||The best way is to find a Unix or Linux user's
group local to you and go to their meetings (you can find links to several
lists of user groups on the LDP
site at Metalab).
(I used to say here that you wouldn't find any real hackers on IRC, but I'm given to understand this is changing. Apparently some real hacker communities, attached to things like GIMP and Perl, have IRC channels now.)
|Q:.||Can you recommend useful books about hacking-related subjects?|
|A:.||I maintain a
Reading List HOWTO that you may find helpful. The
may also be interesting.
For an introduction to Python, see the introductory materials on the Python site.
|Q:.||Do I need to be good at math to become a hacker?|
|A:.||No. While you do need to be able to think logically
and follow chains of exact reasoning, hacking uses very little formal mathematics
In particular, you won't need trigonometry, calculus or analysis (we leave that stuff to the electrical engineers :-)). Some grounding in finite mathematics (including Boolean algebra, finite-set theory, combinatorics, and graph theory) can be helpful.
|Q:.||What language should I learn first?|
|A:.||XHTML (the latest dialect of HTML) if you don't
already know it. There are a lot of glossy, hype-intensive bad
HTML books out there, and distressingly few good ones. The one I like best
The Definitive Guide.
But HTML is not a full programming language. When you're ready to start programming, I would recommend starting with Python. You will hear a lot of people recommending Perl, and Perl is still more popular than Python, but it's harder to learn and (in my opinion) less well designed.
C is really important, but it's also much more difficult than either Python or Perl. Don't try to learn it first.
Windows users, do not settle for Visual Basic. It will teach you bad habits, and it's not portable off Windows. Avoid.
|Q:.||What kind of hardware do I need?|
|A:.||It used to be that personal computers were rather
underpowered and memory-poor, enough so that they placed artificial limits
on a hacker's learning process. This stopped being true some time ago;
any machine from an Intel 486DX50 up is more than powerful enough for development
work, X, and Internet communications, and the smallest disks you can buy
today are plenty big enough.
The important thing in choosing a machine on which to learn is whether its hardware is Linux-compatible (or BSD-compatible, should you choose to go that route). Again, this will be true for most modern machines. The only real sticky area is modems; some machines have Windows-specific hardware that won't work with Linux.
There's a FAQ on hardware compatibility; the latest version is here.
|Q:.||I want to contribute. Can you help me pick a problem to work on?|
|A:.||No, because I don't know your talents or interests.
You have to be self-motivated or you won't stick, which is why having other
people choose your direction almost never works.
Try this. Watch the project announcements scroll by on Freshmeat for a few days, When you see one that makes you think "Cool! I'd like to work on that!", join it.
|Q:.||Do I need to hate and bash Microsoft?|
|A:.||No, you don't. Not that Microsoft isn't loathsome, but there was a hacker culture long before Microsoft and there will still be one long after Microsoft is history. Any energy you spend hating Microsoft would be better spent on loving your craft. Write good code that will bash Microsoft quite sufficiently without polluting your karma.|
|Q:.||But won't open-source software leave programmers unable to make a living?|
|A:.||This seems unlikely so far, the open-source software industry seems to be creating jobs rather than taking them away. If having a program written is a net economic gain over not having it written, a programmer will get paid whether or not the program is going to be open-source after it's done. And, no matter how much "free" software gets written, there always seems to be more demand for new and customized applications. I've written more about this at the Open Source pages.|
|Q:.||How can I get started? Where can I get a free Unix?|
|A:.||Elsewhere on this page I include pointers to where to get the most commonly used free Unix. To be a hacker you need motivation and initiative and the ability to educate yourself. Start now...|