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                         The Unix Koans of Master Foo

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Master Foo and the Ten Thousand Lines

  Master Foo once said to a visiting programmer: “There is more
  Unix-nature in one line of shell script than there is in ten thousand
  lines of C.”

  The programmer, who was very proud of his mastery of C, said: “How can
  this be? C is the language in which the very kernel of Unix is
  implemented!”

  Master Foo replied: “That is so. Nevertheless, there is more
  Unix-nature in one line of shell script than there is in ten thousand
  lines of C.”

  The programmer grew distressed. “But through the C language we
  experience the enlightenment of the Patriarch Ritchie! We become as one
  with the operating system and the machine, reaping matchless
  performance!”

  Master Foo replied: “All that you say is true. But there is still more
  Unix-nature in one line of shell script than there is in ten thousand
  lines of C.”

  The programmer scoffed at Master Foo and rose to depart. But Master Foo
  nodded to his student Nubi, who wrote a line of shell script on a
  nearby whiteboard, and said: “Master programmer, consider this
  pipeline. Implemented in pure C, would it not span ten thousand lines?”

  The programmer muttered through his beard, contemplating what Nubi had
  written. Finally he agreed that it was so.

  “And how many hours would you require to implement and debug that C
  program?” asked Nubi.

  “Many,” admitted the visiting programmer. “But only a fool would spend
  the time to do that when so many more worthy tasks await him.”

  “And who better understands the Unix-nature?” Master Foo asked. “Is it
  he who writes the ten thousand lines, or he who, perceiving the
  emptiness of the task, gains merit by not coding?”

  Upon hearing this, the programmer was enlightened.

Master Foo and the Script Kiddie

  A stranger from the land of Woot came to Master Foo as he was eating
  the morning meal with his students.

  “I hear y00 are very l33t,” he said. “Pl33z teach m3 all y00 know.”

  Master Foo's students looked at each other, confused by the stranger's
  barbarous language. Master Foo just smiled and replied: “You wish to
  learn the Way of Unix?”

  “I want to b3 a wizard hax0r,” the stranger replied, “and 0wn
  ever3one's b0xen.”

  “I do not teach that Way,” replied Master Foo.

  The stranger grew agitated. “D00d, y00 r nothing but a p0ser,” he said.
  “If y00 n00 anything, y00 wud t33ch m3.”

  “There is a path,” said Master Foo, “that might bring you to wisdom.”
  The master scribbled an IP address on a piece of paper. “Cracking this
  box should pose you little difficulty, as its guardians are
  incompetent. Return and tell me what you find.”

  The stranger bowed and left. Master Foo finished his meal.

  Days passed, then months. The stranger was forgotten.

  Years later, the stranger from the land of Woot returned.

  “Damn you!” he said, “I cracked that box, and it was easy like you
  said. But I got busted by the FBI and thrown in jail.”

  “Good,” said Master Foo. “You are ready for the next lesson.” He
  scribbled an IP address on another piece of paper and handed it to the
  stranger.

  “Are you crazy?” the stranger yelled. “After what I've been through,
  I'm never going to break into a computer again!”

  Master Foo smiled. “Here,” he said, “is the beginning of wisdom.”

  On hearing this, the stranger was enlightened.

Master Foo Discourses on the Two Paths

  Master Foo instructed his students:

  “There is a line of dharma teaching, exemplified by the Patriarch
  McIlroy's mantra ‘Do one thing well’, which emphasizes that software
  partakes of the Unix way when it has simple and consistent behavior,
  with properties that can be readily modeled by the mind of the user and
  used by other programs.”

  “But there is another line of dharma teaching, exemplified by the
  Patriarch Thompson's great mantra ‘When in doubt, use brute force’, and
  various sutras on the value of getting 90% of cases right now, rather
  than 100% later, which emphasizes robustness and simplicity of
  implementation.”

  “Now tell me: which programs have the Unix nature?”

  After a silence, Nubi observed:

  “Master, these teachings may conflict.”

  “A simple implementation is likely to lack logic for edge cases, such
  as resource exhaustion, or failure to close a race window, or a timeout
  during an uncompleted transaction.”

  “When such edge cases occur, the behavior of the software will become
  irregular and difficult. Surely this is not the Way of Unix?”

  Master Foo nodded in agreement.

  “On the other hand, it is well known that fancy algorithms are brittle.
  Further, each attempt to cover an edge case tends to interact with both
  the program's central algorithms and the code covering other edge
  cases.”

  “Thus, attempts to cover all edge cases in advance, guaranteeing
  ‘simplicity of description’, may in fact produce code that is
  overcomplicated and brittle or which, plagued by bugs, never ships at
  all. Surely this is not the Way of Unix?”

  Master Foo nodded in agreement.

  “What, then, is the proper dharma path?” asked Nubi.

  The master spoke:

  “When the eagle flies, does it forget that its feet have touched the
  ground? When the tiger lands upon its prey, does it forget its moment
  in the air? Three pounds of VAX!”

  On hearing this, Nubi was enlightened.

Master Foo and the Methodologist

  When Master Foo and his student Nubi journeyed among the sacred sites,
  it was the Master's custom in the evenings to offer public instruction
  to Unix neophytes of the towns and villages in which they stopped for
  the night.

  On one such occasion, a methodologist was among those who gathered to
  listen.

  “If you do not repeatedly profile your code for hot spots while tuning,
  you will be like a fisherman who casts his net in an empty lake,” said
  Master Foo.

  “Is it not, then, also true,” said the methodology consultant, “that if
  you do not continually measure your productivity while managing
  resources, you will be like a fisherman who casts his net in an empty
  lake?”

  “I once came upon a fisherman who just at that moment let his net fall
  in the lake on which his boat was floating,” said Master Foo. “He
  scrabbled around in the bottom of his boat for quite a while looking
  for it.”

  “But,” said the methodologist, “if he had dropped his net in the lake,
  why was he looking in the boat?”

  “Because he could not swim,” replied Master Foo.

  Upon hearing this, the methodologist was enlightened.

Master Foo Discourses on the Graphical User Interface

  One evening, Master Foo and Nubi attended a gathering of programmers
  who had met to learn from each other. One of the programmers asked Nubi
  to what school he and his master belonged. Upon being told they were
  followers of the Great Way of Unix, the programmer grew scornful.

  “The command-line tools of Unix are crude and backward,” he scoffed.
  “Modern, properly designed operating systems do everything through a
  graphical user interface.”

  Master Foo said nothing, but pointed at the moon. A nearby dog began to
  bark at the master's hand.

  “I don't understand you!” said the programmer.

  Master Foo remained silent, and pointed at an image of the Buddha. Then
  he pointed at a window.

  “What are you trying to tell me?” asked the programmer.

  Master Foo pointed at the programmer's head. Then he pointed at a rock.

  “Why can't you make yourself clear?” demanded the programmer.

  Master Foo frowned thoughtfully, tapped the programmer twice on the
  nose, and dropped him in a nearby trashcan.

  As the programmer was attempting to extricate himself from the garbage,
  the dog wandered over and piddled on him.

  At that moment, the programmer achieved enlightenment.

Master Foo and the Old Hand

  An experienced Unix programmer, hearing of Master Foo's wisdom, came to
  him for guidance. Approaching the Master, he bowed three times and
  said:

  “Master Foo, I am gravely troubled. In my youth, those who followed the
  Great Way of Unix used software that was simple and unaffected, like ed
  and mailx. Today, they use vim and mutt. Tomorrow I fear they will use
  KMail and Evolution, and Unix will have become like Windows — bloated
  and covered over with GUIs.”

  Master Foo said: “But what software do you use when you want to draw a
  poster?”

  The programmer replied: “I...have never done that. But I am sure that I
  could use LaTeX or pic to accomplish it without GUIs, in the proper
  Unix way.”

  Master Foo then said: “Which one will reach the other side of the
  river: The one who dreams of a raft, or the one that hitchhikes to the
  next bridge?”

  Upon hearing this, the programmer was enlightened.

Master Foo and the Shell Tools

  A Unix novice came to Master Foo and said: “I am confused. Is it not
  the Unix way that every program should concentrate on one thing and do
  it well?”

  Master Foo nodded.

  The novice continued: “Isn't it also the Unix way that the wheel should
  not be reinvented?”

  Master Foo nodded again.

  “Why, then, are there several tools with similar capabilities in text
  processing: sed, awk and Perl? With which one can I best practice the
  Unix way?”

  Master Foo asked the novice: “If you have a text file, what tool would
  you use to produce a copy with a few words in it replaced by strings of
  your choosing?”

  The novice frowned and said: “Perl's regexps would be excessive for so
  simple a task. I do not know awk, and I have been writing sed scripts
  in the last few weeks. As I have some experience with sed, at the
  moment I would prefer it. But if the job only needed to be done once
  rather than repeatedly, a text editor would suffice.”

  Master Foo nodded and replied: “When you are hungry, eat; when you are
  thirsty, drink; when you are tired, sleep.”

  Upon hearing this, the novice was enlightened.

Master Foo and the Nervous Novice

  There was a novice who learned much at the Master's feet, but felt
  something to be missing. After meditating on his doubts for some time,
  he found the courage to approach Master Foo about his problem.

  “Master Foo,” he asked “why do Unix users not employ antivirus
  programs? And defragmentors? And malware cleaners?”

  Master Foo smiled, and said “When your house is well constructed, there
  is no need to add pillars to keep the roof in place.”

  The novice replied “Would it not be better to use these things anyway,
  just to be certain?”

  Master Foo reached for a nearby ball of string, and began wrapping it
  around the novice's feet.

  “What are you doing?” the novice asked in surprise.

  Master Foo replied simply: “Tying your shoes.”

  Upon hearing this, the novice was enlightened.

Master Foo and the Recruiter

  A technical recruiter, having discovered that that the ways of Unix
  hackers were strange to him, sought an audience with Master Foo to
  learn more about the Way. Master Foo met the recruiter in the HR
  offices of a large firm.

  The recruiter said, “I have observed that Unix hackers scowl or become
  annoyed when I ask them how many years of experience they have in a new
  programming language. Why is this so?”

  Master Foo stood, and began to pace across the office floor. The
  recruiter was puzzled, and asked “What are you doing?”

  “I am learning to walk,” replied Master Foo.

  “I saw you walk through that door” the recruiter exclaimed, “and you
  are not stumbling over your own feet. Obviously you already know how to
  walk.”

  “Yes, but this floor is new to me.” replied Master Foo.

  Upon hearing this, the recruiter was enlightened.

Master Foo Discourses on Returning to Windows

  A student said: “We have learned that Unix is not just an operating
  system, but also a style of approaching problems.”

  Master Foo nodded in agreement.

  The student continued: “Then, the Great Way of Unix can be applied on
  other operating systems?”

  Master Foo sat silent for a moment, then said: “In every operating
  system there is a path to the Great Way, if only we can find it.”

  The student continued: “What, then, of Windows? It is preinstalled on
  most computers, and though its tools are mostly far inferior, they are
  easy to use for beginners. Surely, Windows users could benefit from the
  Unix philosophy.”

  Master Foo nodded again.

  The student said: “How, then, are those enlightened in the Unix Way to
  return to the Windows world?”

  Master Foo said: “To return to Windows, you have but to boot it up.”

  The student said, growing agitated: “Master Foo, if it is so easy, why
  are there so many monolithic and broken software packages for Windows?
  Elegant software should also be possible with a GUI and fancy colors,
  but there is little evidence that this occurs. What becomes of an
  enlighted one who returns to Windows?”

  Master Foo: “A broken mirror never reflects again; fallen flowers never
  go back to the old branches.”

  Upon hearing this, all present were enlightened.

Master Foo and the Unix Zealot

  A Unix zealot, having heard that Master Foo was wise in the Great Way,
  came to him for instruction. Master Foo said to him:

  “When the Patriarch Thompson invented Unix, he did not understand it.
  Then he gained in understanding, and no longer invented it.”

  “When the Patriarch McIlroy invented the pipe, he knew that it would
  transform software, but did not know that it would transform mind.”

  “When the Patriarch Ritchie invented C, he condemned programmers to a
  thousand hells of buffer overruns, heap corruption, and stale-pointer
  bugs.”

  “Truly, the Patriarchs were blind and foolish!”

  The zealot was greatly angered by the Master's words.

  “These enlightened ones,” he protested, “gave us the Great Way of Unix.
  Surely, if we mock them we will lose merit and be reborn as beasts or
  MCSEs.”

  “Is your code ever completely without stain and flaw?” demanded Master
  Foo.

  “No,” admitted the zealot, “no man's is.”

  “The wisdom of the Patriarchs” said Master Foo, “was that they knew
  they were fools.”

  Upon hearing this, the zealot was enlightened.

Master Foo Discourses on the Unix-Nature

  A student said to Master Foo: “We are told that the firm called Novell
  holds true dominion over Unix.”

  Master Foo nodded.

  The student continued, “Yet we are also told that the firm called
  OpenGroup also holds true dominion over Unix.”

  Master Foo nodded.

  “How can this be?” asked the student.

  Master Foo replied:

  “Novell indeed has dominion over the code of Unix, but the code of Unix
  is not Unix. OpenGroup indeed has dominion over the name of Unix, but
  the name of Unix is not Unix.”

  “What, then, is the Unix-nature?” asked the student.

  Master Foo replied:

  “Not code. Not name. Not mind. Not things. Always changing, yet never
  changing.”

  “The Unix-nature is simple and empty. Because it is simple and empty,
  it is more powerful than a typhoon.”

  “Moving in accordance with the law of nature, it unfolds inexorably in
  the minds of programmers, assimilating designs to its own nature. All
  software that would compete with it must become like to it; empty,
  empty, profoundly empty, perfectly void, hail!”

  Upon hearing this, the student was enlightened.

Master Foo and the MCSE

  Once, a famous Windows system administrator came to Master Foo and
  asked him for instruction: “I have heard that you are a powerful Unix
  wizard. Let us trade secrets, that we may both gain thereby.”

  Master Foo said: “It is good that you seek wisdom. But in the Way of
  Unix, there are no secrets.”

  The administrator looked puzzled at this. “But it is said that you are
  a great Unix guru who knows all the innermost mysteries. As do I in
  Windows; I am an MCSE, and I have many other certifications of
  knowledge not common in the world. I know even the most obscure
  registry entries by heart. I can tell you everything about the Windows
  API, yes, even secrets those of Redmond have half-forgotten. What is
  the arcane lore that gives you your power?”

  Master Foo said: “I have none. Nothing is hidden, nothing is revealed.”

  Growing angry, the administrator said “Very well, if you hold no
  secrets, then tell me: what do I have to know to become as powerful in
  the Unix way as you?”

  Master Foo said: “A man who mistakes secrets for knowledge is like a
  man who, seeking light, hugs a candle so closely that he smothers it
  and burns his hand.”

  Upon hearing this, the administrator was enlightened.

Master Foo and the End User

  On another occasion when Master Foo gave public instruction, an end
  user, having heard tales of the Master's wisdom, came to him for
  guidance.

  He bowed three times to Master Foo. “I wish to learn the Great Way of
  Unix,” he said “but the command line confuses me.”

  Some of the onlooking neophytes began to mock the end user, calling him
  “clueless” and saying that the Way of Unix is only for those of
  discipline and intelligence.

  The Master held up a hand for silence, and called the most obstreperous
  of the neophytes who had mocked forward, to where he and the end user
  sat.

  “Tell me,” he asked the neophyte, “of the code you have written and the
  works of design you have uttered.”

  The neophyte began to stammer out a reply, but fell silent.

  Master Foo turned to the end-user. “Tell me,” he inquired, “why do you
  seek the Way?”

  “I am discontent with the software I see around me,” the end user
  replied. “It neither performs reliably nor pleases the eye and hand.
  Having heard that the Unix way, though difficult, is superior, I seek
  to cast aside all snares and delusions.”

  “And what do you do in the world,” asked Master Foo, “that you must
  strive with software?”

  “I am a builder,” the end user replied, “Many of the houses of this
  town were made under my chop.”

  Master Foo turned back to the neophyte. “The housecat may mock the
  tiger,” said the master, “but doing so will not make his purr into a
  roar.”

  Upon hearing this, the neophyte was enlightened.

Master Foo and the Programming Prodigy

  There was a time when rumors began to reach Master Foo and his students
  of a prodigiously gifted programmer, a young man who wandered the
  length and breadth of the land performing mighty feats of coding and
  humiliating all who dared set their skill against his.

  Eventually this prodigy came to visit Master Foo, who received him
  politely and offered him tea. The Prodigy accepted with equal
  politeness and explained the motive for his visit.

  “I have come to you,” he said “seeking a code and design review of my
  latest project. For it is of surpassing complexity, and I do not have
  peers capable of understanding it. Only an acknowledged master such as
  yourself (and here the Prodigy bowed deeply) can have the discernment
  required.”

  Master Foo bowed politely in return and began examining the Prodigy's
  code. After some time he raised his eyes from the screen. “This code is
  at first sight very impressive,” he said. “It is elegant in design,
  utilizing original algorithms of great ingenuity, and appears to be
  implemented in a craftsmanlike way which minimizes the possibility of
  errors.”

  The Prodigy looked very pleased at this praise, but Master Foo
  continued: “However, I detect one significant flaw.”

  “Flaw?” the Prodigy said. “What flaw?”

  “This code is difficult to read,” said Master Foo. “It is only thinly
  commented, its invariants are not specified, and I see no narrative
  description of its architecture or internal data structures anywhere.
  These problems will seriously impede your cooperation with other
  programmers.”

  The Prodigy drew himself up haughtily. “I do not seek the cooperation
  of other programmers,” he said. “Every time I thought I had found one
  who might match me in skill I have been disappointed. Thus, I work
  alone.”

  “But even the hacker who works alone,” said Master Foo, “collaborates
  with others, and must constantly communicate clearly to them, lest his
  work become confused and lost.”

  “Of what others do you speak?” the Prodigy demanded.

  Master Foo said: “All your future selves.”

  Upon hearing this, the Prodigy was enlightened.

Master Foo and the Hardware Designer

  On one occasion, as Master Foo was traveling to a conference with a few
  of his senior disciples, he was accosted by a hardware designer.

  The hardware designer said: “It is rumored that you are a great
  programmer. How many lines of code do you write per year?”

  Master Foo replied with a question: “How many square inches of silicon
  do you lay out per year?”

  “Why...we hardware designers never measure our work in that way,” the
  man said.

  “And why not?” Master Foo inquired.

  “If we did so,” the hardware designer replied, “we would be tempted to
  design chips so large that they cannot be fabricated - and, if they
  were fabricated, their overwhelming complexity would make it be
  impossible to generate proper test vectors for them.”

  Master Foo smiled, and bowed to the hardware designer.

  In that moment, the hardware designer achieved enlightenment.