Capitalize on binary options without attachments
Softpanorama May the source be with you, but remember the KISS principle ; eBook Perl for system admins This is a very limited effort to help Unix sysadmins to learn of Perl. It is based on my FDU lectures to CS students. We discuss mainly "simple Perl" and the site tries to counter "excessive complexity" drive that is dominant in many Perl-related sites and publications. It can be also used for preparing to the Certified Internet Web Professional Exam. See also Introduction to Perl for Unix system administrators. Systems administrators need options deal with many repetitive task in a complex, changing environment which often includes several different flavors of Unix. Perl is the only scripting language which now is included in all major Unix flavors. That means that it provides the simplest way to automate recurring tasks on multiple platforms. Among typical tasks which sysadmin need to options with: IMHO the main advantage of using powerful complex language like Perl is the ability to write simple programs. Perhaps the world has gone overboard on this object-oriented thing. You do not need many tricks used in lower level languages as Perl itself provides you high level primitives for the task. This page is linked to several sub-pages. The most important among them are: Perl Language assorted language issues and programming tricks Perl a pplications page where I collected links to Perl module for many interesting application area. Please note that it has a companion page Perl development tools. Perl programming environment pagethat might be useful for finding links related to some tools and difficult to understand areas namespaces Perl in SFU All language have quirks, and all inflict a lot of pain before one can adapt to them. Once learned the quirks become incorporated into your understanding of the language. But there is no royal way to mastering the language. Generally any user of a new programming language needs to suffer a lot ;- When mastering a new language first you face a level of "cognitive overload" until the quirks of the language become easily handled by your unconscious mind. At that point, all of the sudden the quirky interaction becomes a "standard" way of performing the task. For example regular expression syntax seems to be a weird base for serious programs, fraught with pitfalls, a big semantic mess as a result of outgrowing its primary purpose. On the other hand, in skilled hands its a very powerful tool that can serve a parser for complex data and a substitute for string functions. There are three notable steps in adaptation to Perl idiosyncrasies for programmers who got used to other languages: Please note that as syntax of Perl is complex the diagnostic in Perl interpreter is really bad. In C one can use pseudo comments that signify nesting level zero and check those points with special program or by writing an editor macro. Many editors have the ability to point to the closing bracket for any given opening bracket and vise versa. This is also useful but less efficient way to solve the problem. Specifying max length of literals is an effecting way of catching missing quote. You can also have an option to limit literal to a single line. In general multi-line literals should have different lexical markers like "here" construct in shell. Some language like Perl provide opportunity to use concatenation operator for splitting literals into multiple line, which are "merged" at compile time. But there is no limit on the number of lines string literal can occupy so this does not help much. If such limit can be communicated via pragma statement at compile type in a particular fragment of text this is an effective way to avoid the problem. Usually only few places in program use multiline literals, if any. Editors that use coloring help to detect unclosed literal problem but there are cases when they are useless. All-in-all Perl is a great language. But even sun has dark spots. I have some doubts about Perl 6, but we will see. Among benefits that Perl bring to system administration are In short if make sense to learn Perl as it makes sysadmin like a lot easier. Probably more so then any other tool in sysadmin arsenal. Be skeptical and do not take recommendations of Perl advocates like Randal Options. Some Perl gurus pathological preoccupation with idioms is definitely not healthy and is part of the problem, not a part of the solution Please remember about KISS principle and try to write capitalize Perl scripts without overly complex regular expressions or fancy idioms. Simplicity has great merits even if goes again current fancy. Generally the problems mentioned above are more fundamental than the trivial "abstraction is the enemy of convenience". It is more like that badly chosen notational abstraction at one level can lead to an inhibition of innovative notational abstraction on others. The key idea here is that any sufficiently flexible and programmable environment — and Perl is such an environment -- gradually begins to take on characteristics of both language and operating system as it grows. Unix shell can actually provide a good "in the large" framework of complex programming system serving as a glue for the components. From the point of view of typical application-level programming Perl is very under appreciated and very little understood language. Almost nobody is interested in details of interpreter, where debugger is integrated with the language really brilliantly. Also namespaces in Perl and OO constructs are very unorthodox and very interesting design. References are Perl innovation: classic CS view is that scripting language should not contain references. Role of list construct as implicit subroutine argument list is also implemented non trivially elements are "by reference" not "by name" and against CS orthodoxy which favors default "by name" passing of arguments. There are many other unique things about design of Perl. All-in-all for real professional like me Perl is one of the few relatively "new" languages that is not boring Syntax of Perl is pretty regular and is favorably compared with the disaster which is syntax of Borne shell and derivatives as well as with syntax of C and C-derivatives. Larry Wall managed to avoid almost all classic pitfalls in creating of the syntax of the language, pitfalls in which creators on PHP readily fell "dangling else" is one example. Debugger for the language is as important as the language itself. Perl debugger is simply great. Incredible from my point of view feat taking into account when it was done. It provided peaceful co-existence with GPL which is no small feat. Dual licensing was a neat, extremely elegant cultural hack to make Perl acceptable both to businesses and the FSF. But it shares several C-style syntax shortcomings and introduced a couple of its own: If more than one variable is listed, the list must be placed in parentheses. With a parenthesized list, undef can be used as a dummy placeholder. However, since initialization of state variables in list context is currently not possible this would serve no purpose. While RStudio has a weak editor it has syntax highlighting and integration with debugger and as such is adequate for medium scripts. There is no similar "established" as standard de-facto GUI for Perl although you can use Orthodox file manage such as Midnight commander, or in Windows Far or Total Commander as poor man IDE. This is not a show stopper for system administrators as they can use screen and mc and generally write mostly small script that can be written and debugged without IDE as well as with IDE. But this is a problem when you try to write program with over 1K lines. Many things in modern IDE helps to avoid typical errors for example identifiers can be picked up from the many by right clicking, braces are easier to match if editor provide small almost invisible vertical rulers, color of the string help to detect running string constants, etc. So wring for Perl virtually guarantee compatibility there is an exception; see note about Perl Hopefully this version will never get into production. In other words no "state" variables if you want "perfect" compatibility. Non perfect but acceptable for Linux deployment compatibility can be achieved by using version which allow you to use "state" variables. For mature language the key area of development is not questionable enhancements, but improvement of interpreter diagnostics and efforts in preventing typical errors which at this point are known. This version allows you to see the list of already declared variables in the program and thus avoid classic "typo in the variable" type of errors. Not all enhancements that Perl developers adopers after version have practical value. Like is done with C or Fortran each 11 years. Support for a couple of useful pragma, for example, the ability to limit the length of string constants to a given length for example for certain parts of the script is absent. Ot something similar like "do not cross the line" limitation. Working with namespaces can and should be improved and rules for Perl namespaces should be much better better documented. Like pointers namespaces provide powerful facity to structuring language programs. Please note that modules are not the only game in town. Actually the way they were constructed has some issues and sometime stupid overemphasis on OO only exacerbate those issues. Multiple entry points in procedures would be probably more useful and more efficient addition to the language. Additional that is very easy to implement. The desire to be capitalize the rest of the pack often backfire. From SE point of view scripting language as VHL stands above OO in pecking order. OO is mainly force feed for low level guys who suffer from Java. For example use of unquoted words as indexes to hashes is definitely a language designers blunder and should be gone. String functions and array functions should be better unified. Exception mechanism should be introduced. Attention: The release contains an obvious bug in regex tokenizer, which now incorrectly requires backslash for number of repetitions part of basic regex symbols. This newly introduced bug aka feature also affects regexes that use opening curvy bracket as a delimiter. Which is a minor but pretty annoying "change we can believe in". I think that idiosyncrasy will prevent spread this version into production version of Linux Unix for a long, long time say years or forever. The author covers the perlbrew utility. What about all of us schmucks that are stuck with Windows at work, or elsewhere? Throw us a bone!! He covers the community! Case in point, the warning on page 13 regarding the old OO docs that came with and Wonderful. Chapter An entire chapter on CPAN? CPAN is a great resource, and part of what binary Perl so great The author even has some advice regarding how to evaluate a module. That is quickly becoming the favorite of a lot of people. It is great that the author covers the various cpan clients. However, if you end up in a shop like mine, that ends up being useless as you have to beg some sysadmin for every module you want installed. Chapter The basics of Perl are covered here in a very thorough way. The author takes you from "What is programming? Chapter Much more useful stuff is contained in this chapter. Herein lies another one of those wonderful grey boxes. The author even has a section to warn you against your temptation to use the "Switch" module. Chapter Wow references so early in the book!?!? Upon reflecting a bit, I think this is a good move. Chapter I do find it odd that a chapter on subroutines comes after a chapter on references, though. It seems like subroutines are the obvious choice to get a beginning programmer to start organizing their code. Hence, it should have come earlier. It reads so well! Of course, it is obvious now that references needed to be discussed first, or this technique would just be "black magic" to a new Perl person. There are so many other good things in this chapter: Carp, Try::Tiny, wantarray, Closures, recursion, etc. This is definitely a good chapter to read a couple of times and experiment with the code. Chapter As the author points out, an entire book has been written on the topic of regular expressions perhaps even more than one book. Yes, yes there is, and it is well worth reading. I find it a bit odd that POD comes up in this chapter, rather than somewhere else. I guess it makes sense here, but would you really not document until you got to this point? I think you get a good feel for the "old school" version that you are likely to see in old code bases with a good comparison of how that can be easier by using Moose. These two chapters are worth reading a few times and playing with some code. Chapter Unit testing for the win! I loved seeing this chapter. I walked into a shop with zero unit tests and have started the effort. Testing has been part of the Perl culture since the beginning. Chapter "The Interwebs", really? Plack is covered, yay!!! Actually, this is a good overview of "web programming", and just "how the web works". Chapter A chapter on DBI? How about "The chapter about STDIN, STDOUT, and STDERR". Including the debugger and a profiler is good. However, how do you use the debugger with a web app? I could be wrong. In any case, a little more on debugger scenarios would have been helpful. A lot of those comments also apply to profiling. I hope I just missed that stuff in this chapter Chapter Wow, the sort of "leftover" chapter, yet still useful. Quick coverage of templates and web frameworks? Having said that, there are probably tons of shops that use it like mine until their employees demand that it be deleted from systems without remorse. So, it probably should have been given at least some lip service. I am an admitted "fanboy" of Ovid. Given that, I can see how you might think I got paid for this or something. I just think that he did a great job covering Options with this book He gives you stuff here that other authors have separated into multiple books. Instead of use v5. This article offers a sampling of recipes that let you perform common tasks with LWP. It lists new files in CPAN in the past two weeks. While LWP consists of dozens of classes, the two that you have to understand are LWP::UserAgent and HTTP::Response. A "cookie jar" is an object representing a little database of all the HTTP cookies that a browser can know about. LWP::UserAgent objects have many attributes for controlling how they work. For more options and information, see the full documentation for LWP::RobotUA. In some cases, you will want to or will have to use proxies for accessing certain sites or for using certain protocols. This is most commonly the case when your LWP program is running or could be running on a machine that is behind a firewall. The simplest way to let the browser know about this is to use the credentials method to let it know about a username and password that it can try using for that realm at that host. A notable alternative is to have LWP save the content to a file on disk, instead of saving it up in memory. Read sample chapters online The LWP Library for WWW in Perl suite of modules lets your programs download and extract information from the Web. This book is a must have for Perl programmers who want to automate and mine the Web. For such a deep subject, this book weighs in at a slim pages. This is a very good thing. It covers everything you need to know with concise examples, which is what makes this book really shine. You start with the basics using LWP::Simple through to more advanced topics using LWP::UserAgent, HTTP::Cookies, and WWW::RobotRules. Sean shows finger saving tips and shortcuts that take you more than a couple notches above what you can learn from the lwpcook manpage, with enough depth to satisfy somebody who is an experienced LWP hacker. The book ends with a chapter on spidering, with excellent coverage of design and warnings to get your started on your web trawling. No one else will be able to get to that file because no one else has the name for it. If my perl is compiled with PerlIO it probably isI can open a filehandle on a scalar variable if the filename argument is a reference to that variable. Most Unix programmers probably already know that they can read the output from a command as the input for another command. But, I can have more than one command in that pipeline. David Farrell showed some of this in How to redirect and restore STDOUT. Perl v is bringing myriad new features and ways of doing things, making its perldelta file much more interesting than most releases. It has the same meta-character problem as the two-argument open. Special characters in the filename might do shell things. You can still find these modules on CPAN, though. It did everything, including HTML generation. Somehow, Module::Build fell out of favor. Before then, building and installing Perl modules depended on a non-perl tool, make. However, we already know they have Perl, so if there were a pure Perl tool that could do the same thing we could solve the portability problem. We could also do much more fancy things. It was the wave of the future. This highlights a long-standing and usually undiscovered problem with modules that depend on modules in the Standard Library. For years, most authors did not bother to declare those dependencies because Perl was there and its modules must be there too. When options modules move to a CPAN-only state, they end up with an undeclared dependencies. This also shows up in some linux distributions that violate the Perl license by removing some modules or putting them in a different package. Either way, always declare a dependency on everything you use despite its provenance. Have you always felt too constrained by ten digits, but were also stuck with non-integers? Now your problems are solved with hexadecimal floating point numbers. We already have the exponential notation with uses the e to note the exponent, as in e4. This creates an alias for the referenced value. We can now assign to something other than a scalar for the foreach control variable: use v5. Perl can assign one list of scalars to another. In Learning Perl we show assigning to undef. Those in the unix world know as a special filename for standard input in many commands. We also get many smaller fixes I think are worth a shout out. Many of these are clean ups to warts and special cases: An anonymous reader writes: Last night Larry Wall unveiled the first development release of Perl 6joking that now a top priority was fixing bugs that could be mistaken for features. The new language features meta-programming — the ability to define new bits of syntax on your own to extend the binary, and even new infix operators. Larry also previewed what one reviewer called "exotic and new" features, including the sequence operator and new control structures like "react" and "gather and take" lists. That still leaves Lua and Stackless Python as the only languages with symmetric, transparent coroutines without playing games with the C stack. Neither Lua nor Stackless Python implement recursion on the C stack. Javascript is similarly crippled. So in Lua you can use coroutines to implement great algorithms without thinking twice. Kernel threads and "fibers" are comparatively heavy weight, both in terms of performance and memory, compared to VM-level coroutines. I was looking forward to Perl 6. The top two language abstractions I would have loved to see were coroutines and lazy evaluation. Perl6 capitalize poor approximations of those things. And of course the "most used" patterns are that way because of existing language limitations. I was really looking forward to Perl6 I always liked Perl 5but it remains the case that the only interesting language alternative in my space are Go and Rust. Too many Rust developers are desktop GUI and game developers with a very narrow, skewed experience about dealing with allocation and other resource failures Even Lua can handle OOM trivially and cleanly without trashing the whole VM or unwinding the entire call stack. So that basically just leaves Go, which is looking better and better. Not surprising given how similar Go and Lua are. And you have to meet it half way. Well you CAN write maintainable code in perl, you just have to use binary discipline. Turn "use strict;" on everywhere, break your project up into packages across functional lines and have unit tests on everything. You know, all that stuff that no companies ever do. I have lots of headache in Every Single One of the database middleware Except DBI. Say what you want about Perl 5 without it is still one of the fastest interpreted languages around. The cool kids jumped on the python bandwagon saying perl was old, but in all this time they have yet failed to: Beginning with Perlyou can declare variables with the state keyword in place of my For that to work, though, you must have enabled that feature beforehand, either by using the feature pragma, or by using -E on one-liners see feature. Beginning with Perlthe CORE::state form does not require the feature pragma. The state keyword creates a lexical variable following the same scoping rules as my that persists from one subroutine call to the next. If a state variable resides inside an anonymous subroutine, then each copy of the subroutine has its own copy of the state variable. However, the value of the state variable will still persist between calls to the same copy of the anonymous subroutine. When such statements are evaluated subsequent times, the assignment is ignored. The behavior of this sort of assignment to non-scalar variables is undefined. It normally works more like a C auto, but with implicit garbage collection. If something more permanent is still aware of the lexical, it will stick around. Automatic garbage collection takes care of this for you. This means that you can pass back or save away references to lexical variables, whereas to return a pointer to a C auto is a grave error. They are available to all functions in that same file declared below them, but are inaccessible from outside that file. This strategy is sometimes used in modules to create private variables that the whole module can see. I first heard of Perl when I was in middle school in the early s. But compared to its rival Python, Perl has faded from popularity. A central repository the Comprehensive Perl Archive Network, or CPAN meant that for every person who wrote code, many more in the Perl community the Programming Republic of Perl could employ it. This, along with the witty evangelism by eclectic creator Larry Wallwhose interest in language ensured that Perl led in text parsing, was a formula for success during a time in which lots of text information was spreading over the Internet. As the 21st century approached, many pearls of wisdom were wrought to move and analyze information on the web. Perl did have a learning curve—often meaning that it binary the third or fourth language learned by adopters—but it sat at the top of the stack. Meanwhile, Perl is the fastest SUV, coming up in front of all the other SUVs. Of course, we all know Perl is in a class of its own. Well, the millennium passed, computers survived Y2Kand my teenage years came and went. My knowledge of Perl remained like the start of a new attachments file cursoryfollowed by a lot of blank space to fill up. In college, CS friends at Princeton raved about Python as their favorite language in spite of popular professor Brian Kernighan on campus, who helped popularize C. I thought Python was new, but I later learned it was around when I grew up as well, just not visible on the charts. By the late s Python was not only the dominant alternative to Perl for many text parsing tasks typically associated with Perl i. Both are frequently referred to as "scripting languages," even though later versions are retro-fitted with object oriented programming OOP capabilities. Stylistically, Perl and Python have different philosophies. Python is designed to have one obvious way to do it. But over the course of the last 15 yearsnot only how companies do business has changed and grown, but so have the tools they use to have grown as well, unequally to the detriment of Without. At the Orlando Perl Workshop inone of the talks was titled " Perl is not Dead, It is a Dead End ," and claimed that Perl now existed on an island. Once Perl programmers checked out, they always left for good, never to return Others point out that Perl is left out of the languages to learn first —in an era where Python and Java had grown enormously, and a new entrant from the mid s, Ruby, continues to gain ground by attracting new users in the web application arena via Railsfollowed by the Django framework in Python PHP has remained stable as the simplest option as well. How has Perl become the underdog, and can this trend be reversed? And, perhaps more importantly, will Perl 6 be released!? Why Attachmentsand not Perl? Perhaps an illustrative example of what happened to Perl is my own experience with the language. In college, I still stuck to the contained environments of Matlab and Mathematica, but my programming perspective changed dramatically in I realized lacking knowledge of structured computer code outside the "walled garden" of a desktop application prevented me from fully simulating hypotheses about the natural world, let alone analyzing data sets using the web, which was also becoming an increasingly intellectual and financially lucrative skill binary. One year after college, I resolved to learn a "real" programming language in a serious manner An all-in immersion taking me over the hump of knowledge so that, even if I took a break, I would still retain enough to pick up where I left off. An older alum from my college who shared similar interests—and an experienced programmer since the late s—convinced me of his favorite language to sift and sort through text in just a few lines of code, and "get things done": Perl. Python, he dismissed, was what "what academics used to think. Yet once again, Python reared its headand even Perl forums and sites dedicated to the language were lamenting the digital siege their language was succumbing to. What happened to Perl? Ultimately undeterred, I found enough to get started quality over quantity, I figured! But it was not to be. I had adopted Perl for text analysis, but upon accepting an engineering graduate program offer, switched to Python to prepare. This has created a lot of issues with importing pointed out by Walland package download synchronizations to get scientific computing libraries as I foundbut has also resulted in distributions of Python such as Anaconda that incorporate the most important libraries besides the standard library to ease the time tariff on imports. ByPython was the language of choice in academia, where I was to return for a year, and whatever it lacked in OOP classes, it made up for in college classes. Python was like Google, who helped spread Python and employed van Rossum for many years. Meanwhile, its adversary Yahoo largely developed in Perl did well, but comparatively fell further behind in defining the future of programming Python was the favorite and the incumbent; roles had been reversed. To see the rise of Python and the fall of Perl in more empirical terms, check out the following heuristics. Job listings or search engine hits could mean that a programming language has many errors and issues with it, or that there is simply a large temporary gap between supply and demand. The concomitant picture, and one that many in the Perl community now acknowledge, is that Perl is now essentially a second-tier language, one that has its place but will not be the first several languages known outside of the Computer Science domain such as Java, C, or now Python. I believe Perl has a futurebut it could be one for a limited audience. Present-day Perl is more suitable to users who have worked with the language from its early daysalready dressed to impress. And the high activation cost of learning Perl, instead of implementing a Python solution. Ironically, much in the same way that Perl jested at other languages, Perl now finds itself at the receiving end. Absent a game-changing Perl release which still could be "too little, too late" people who learn to program in Python have no need to switch if Python can fulfill their needs, even if it is widely regarded as second or third best in some areas. The fact that you have to import a library, or put up with some extra syntax, is significantly easier than the transactional cost of learning a new language and switching to it. For example, at MIT Python replaced Scheme as the first language of instruction for all incoming freshman, in the mid s. While none of these efforts are centrally coordinated by van Rossum himself, a continually expanding user base, and getting to CS students first before other languages such as even Java or Cincreases the odds that collaborations in disciplines will emerge to build a Python library for themselves, in the same open source spirit that made Perl a success in the s. Perhaps Perl 6 will be that release. However, in the interim, I have heeded the advice of many others with a similar dilemma on the web. This is the new edition, updated for and As usual, these electronic versions are free to download. Please share them with friends, family, colleagues, coworkers, and interested people. I hope to have those available in the next couple of weeks, but that depends on how much more debugging we have to do. Syed A: I used to teach sysadmins Perl in corporate environment and I can tell you that the main danger of learning Perl for system administrator is overcomplexity that many Perl books blatantly sell In this sense anything written by Randal L. Schwartz is suspect and Learning Perl is a horrible book to start. And only then gradually start writing full-blown Perl scripts. For inspiration you can look collection on Perl one-liners but please beware that some many of them are way too clever to be useful. Useless overcomplexity rules here too. I would also recommend to avoid OO features on Perl that many books oversell. A lot can be done using regular Algol-style programming with subroutines and by translating awk into Perl. OO has it uses but like many other programming paradigms it is oversold. Perl is very well integrated in Unix better then any of the competitors and due to without it opens for sysadmin levels of productivity simply incomparable with those levels that are achievable using shell. You can automate a lot of routine work and enhance existing monitoring systems and such with ease if you know Perl well. It is similar in function to SecureCRT or Putty. It also serves to de-couple dependency checking and the workflow execution engine from the rest of your program with the caveat that your program may need to interpret the output from make Perl::Critic is an extensible framework for creating and applying coding standards to Perl source code. Essentially, it is a static source code analysis engine. It is distributed with a number of Perl::Critic::Policy modules that attempt to enforce various coding guidelines. However, Perl::Critic is not limited to PBP, and will even support Policies that contradict Conway. You can enable, disable, and customize those Polices through the Perl::Critic interface. You can also create new Policy modules that suit your own tastes Tags: Perl Admin ToolsPerlProgramming styleProgram UnderstandingPAC provides a GUI to configure SSH and Telnet connections, including usernames, passwords, EXPECT regular expressions, and macros. Do you have any suggestion what this schould be about? Garry - I began my career on sys5 rel 3. There is one indisputable fact on the ground that we need to remember discussing this topic in context of enterprise Unix environment: Typically in a large corporation sysadmin need to support two or more flavors of Unix. In many organizations installation of additional scripting language on all Unix boxes is a formidable task that requires political support on pretty high level of hierarchy. My God, even to make bash available on all boxes is an almost impossible task When is an extremely simple personal calendar program, aimed at the Unix geek who wants something minimalistic. It treats dogmatism as damage and routes around it. As Larry wrote, it is trollish in its nature But its friendly, playful brand of trollishness is what allows it to continue to evolve as a culture. One of the worst things a programmer can do is invest too much ego, pride or seriousness in his work. Just as Perl is a technology of technological hacking, so too Perl is a culture of cultural hacking. You can see some of those hacks in that mirror you are holding. Er…that is holding you. The second big cultural hack was demonstrating to Unix culture that its reductionistic ideas could be subverted and put to use in a non-reductionistic setting Yet another well-known hack was writing a computer book that was not just informative but also, gaspentertaining! But these are all shallow hacks. Each has their niche. My issues with Perl is when people get Overly Obfuscated with their code because the person thinks that less characters and a few pointers makes the code faster. Unless you do some real smart OOesque building all you are doing is making it harder to figure out what you were thinking about. If written properly Perl is very efficient code. Also if we think about all dull, stupid and unrelaible Java coding of large business applications that we see on the marketplace the question arise whether we want this type of success ;- Douglas: Mastering Perl requires slightly higher level of qualification from developers then "Basic-style" development in PHP or commercial Java development where Java typically plays the role of Cobol which is mainstream those days. Also many important factors are outside technical domain: ecosystem for Java is tremendous and is supported by players with deep pockets. Same is true for Python. Still Perl has unique advantages, is universally deployed on Unix and as such is and always will be attractive for thinking developers I think that for many large business applications which in those days often means Web application with database backend one can use virtual appliance model and use OS facilities for multitasking Nothing wrong with this approach on modern hardware. Here Perl provides important advantages due to good integration with Unix. Also structuring of a large application into modules using pipes and sockets as communication mechanism often provides very good maintainability. Pointers are also very helpful and unique for Perl. Typically scripting languages do not provide pointers. Perl does and as such gives the developer unique power and flexibility with additional risks as an inevitable side effect. Another important advantage of Perl is that it is a higher level language then Python to say nothing about Java and stimulates usage of prototyping which is tremendously important for large projects as the initial specification is usually incomplete and incorrect. Look at IBM fiasco with Lotus Notes I think that Perl is great in a way it integrates with Unix and promote thinking of complex applications as virtual appliances. BTW this approach also permits usage of a second language for those parts of the system for which Perl does not present clear advantages. Also Perl provide an important bridge to system administrators who often know the language and can use subset of it productively. That makes it preferable for large systems which depend on customization such as monitoring systems. I wonder why ActiveState missed this opportunity to increase its revenue stream. Perl provides a clean implementation of the concept of namespaces. Because, despite what some hard-core Perl programmers might say, the language is somewhat dated. This may in fact be one of the problems in selling it to people nowadays. It was taken out of the OS shortly after the bust and committee reorganization at FreeBSD, where it was moved into third-party software. The package-management scripts were re-written in C. Other package management utilities were effectively displaced by a Ruby package. I suppose the Moose augmentation of Perl would have some appeal with that, but CPAN modules and addons like Moose are not REALLY the Perl language itself So if we are talking about selling the Perl language alone to potential adopters, you have to be honest in discussing the merits of the language itself without all the extras. But there is a substantial role for high-level batching languages, particularly in systems that build data for consumption by other systems. These are traditionally implemented in the highest-level batching language possible. Such systems build things like help files, structured non-relational databases often used on high-volume commercial web servicesand software. Not to mention automation many systems administration tasks. There are not too many features or advantages to Perl that are unique in itself in the realm of scripting languages, as they were in the 90s. The simplicity of built-in Perl data structures and regular expression capabilities are reflected almost identically in Ruby, and are at least accessible in other strongly-typed languages like Java and C. The fact that Perl is easy to learn, and holds consistent with the idea that "everything is a string" and there is no need to formalize things into an object-oriented model are a few of its selling points. There is no advantage to bytecode over interpreted. When you bless a reference in to an object it becomes and object. Ultimately the objects are all converted in to machine code and executed. In general perl objects are more object oriented than java objects. They are certainly more polymorphic. Perl objects can fully hide their internals if thats something you want to do. But does it afford any real benefit? At the end of the day, if you want good software you need to hire good programmers it has nothing to do with the language. Even though some languages try to force the code to be neat Python and try to force certain behaviours Java? A syntactic argument is pointless. As is something oriented around OO. Believe me, I have written more vanilla C code in my career than Perl or Python, by a factor of thousands, yet I still prefer Python or Perl as quite simply a more succinct expression of the intended algorithm. If anyone wants to argue the meaning of "high level", well basically APL wins ok. In APL, to invert a matrix is a single operator. Meanwhile, Python or Perl are pretty convenient. What I mean by a "high level language" is basically how many pages of code does it take to play a decent game of draughts chequersor chess? Another way to process the content from tcpdump is to save the raw network packet data to a file and then process the file to find and decode the information that you want. There are a number of modules in different languages that provide functionality for reading and decoding the data captured by tcpdump and snoop. For example, within Perl, there are two modules Net::SnoopLog for snoop and Net::TcpDumpLog for tcpdump. These will read the raw data content The basic interfaces for both of these modules is the same. To binary, first you need to create a binary record of the packets going past on the network by writing out the data to a file using either snoop or tcpdump. Once you have amassed the network data, you can start to process the network data contents to find the information you want. For example, Listing shows a simple script that prints out the IP address information for all of the packets. The Net::TcpDumpLog module serializes each packet, so that we can read each packet by using the packet ID. The data method then returns the raw data for the entire packet. As with the output from snoop, we have to extract each of the blocks of data from the raw network packet information. So in this example, we first need to extract the ethernet packet, including the data payload, from the raw network packet. The NetPacket::Ethernet module does this for us. Since we are looking for IP packets, we can check for IP packets by looking at the Ethernet packet type. IP packets have an ID of 0x The NetPacket::IP module can then be used to extract the IP information from the data payload of the Ethernet packet. The module provides the source IP, destination IP and protocol information, among others, which we can then print. Using this basic framework you can perform more complex lookups and decoding that do not rely on the automated solutions provided by tcpdump or snoop. For example, if you suspect that there is HTTP traffic going past on a non-standard port i. Obviously, in this example, we are dumping out the raw data, but you could use the same basic structure to decode and the data in any format using any public or proprietary protocol structure If you are using or developing a protocol using this method, and know the protocol format, you could extract and monitor the data being transferred. That installation is as simple as downloading the standalone version and chmodding is a nice touch. It actually left the light on for you, and put the toilet seat down. Wade Johnson "You had me at --thpppt. People are all over it. The ability to control the search domain by filetype--and to do so independent of platform--has made one-liners out of many complex queries previously done with custom scripts. Parrot developers are hooked on ack. People see me using it and ask what the heck it is. If you want no dependency on the environment, turn it off with --noenv. Ignored if output is redirected nopager Do not send output through a pager. File finding f Only print the files found, without searching The PATTERN must not be specified g REGEX Same as -f, but only print files matching REGEX sort-files Sort the found files lexically. Analyzing Ethernet LAN Traffic -- Paul Barry Download Volume 0 Issue January k PDF Jotto: The Five-Letter Word Game -- Kevin Jackson-Mead Processing RSS Files with XSLT -- Dr. Perl gives you unlink and rename to remove and rename files. And you can manage and modify those processes directly as well. Hopefully, you can see from these lists that Perl provides a rich set of interfaces to low-level operating system details. When the subject of Perl was brought up here at the Pingdom office, we were not sure how widely used it is now inespecially on the Web. The above websites are just the tip of the iceberg, though. Here are even more examples of sites making extensive use of Perl: Add to this all blogs using the Movable Type blogging software from Six Apart, which uses Perl. And of course all blogs on the Typepad blogging service, which uses a special version of Movable Type. Inside the Perl community, people know it is widely used. At least one Alexa top website is fully coded in Perl and several other top sites partially use it. Just look as the example code included in the comments here. Not much to choose between them really save your proselytizing. Next year you will see the first bundled releases of Perl6 in the mainstream distributions Where there was once ridicule aimed at a still unreleased Perl6, there will be surprise, relief, interest and adopters. Books attachments be published and take up shelf space in the computer departments of book shops. It will be noticed and newbies will want to give it a try. Old Perl hands will take a look at it, and some Python and Ruby diehards will also consider their options though most will stay put because that is how people are. Next year interest in Perl will grow. Just take a look at Google trends; the interest is already building. Next year, and increasingly, it will be Perl6 which is the new kid on the block, and Python and Ruby will be the oldies who struggle to keep up. Could be binary though. You can never tell Not only is Perl still popular for web sites, it is gaining in the field of bio-analysis. As most Perl fans are no doubt aware, the Perl Foundation released version last month and introduced a number of significant upgrades for the popular programming language Perl is the first significant feature upgrade since the release back in First the good news, AKA why you should go ahead and upgrade: the major new language features are turned off by default which means you can upgrade without breaking existing scripts, and take advantage of the new features for new scripts. Other improvements include a faster interpreter with a smaller memory footprint, better error messages and more. For full details on the new release check out the notes. The simplest regular expressions are matching expressions. They perform tests using keywords like ifwhile and unless. If you want to be really clever, you can use them with and and or. A matching regexp will return a true value if whatever you try to match occurs inside a string. A metacharacter is a character or sequence of characters that has special meaning. Regular expressions have a rich vocabulary of metacharacters that let you ask interesting questions such as, "Does this expression occur at the end of a string? These indicate "beginning of string" and "end of string," respectively. Perl is a bit more complex, but works on the same general principle. In Perl, the generic wildcard character is A period inside a regular expression will match any character, except a capitalize. To match a literal metacharacter, escape it with a backslash. If you only want to match a string that actually contains "Mr. Each quantifier means something different. The quantifier is the easiest to understand: It means to match the immediately preceding character or metacharacter one or more times. This is different from the quantifier! The URL-matching code can be more concise with these metacharacters. To understand what this does, read from left to right: This regex will match any string that starts with "http:" followed by one or more occurences of any characterand ends with "html". For example, you might need to verify that a string contains an American-style phone number, which has the form You could use code like this: use ; say "Not a phone number! Fortunately, Perl can do better Use numbers inside curly braces to indicate a quantity you want to match: use ; say "Not a phone number! To use a range of numbers, you can separate them with a comma; leaving out the second number makes the range open-ended. You define a character class by enclosing a list of the allowable characters in square brackets. You can place flags after a attachments to modify their behaviour. One of the more interesting things you can do with regular expressions is subexpression matchingor grouping. A subexpression is another, smaller regex buried inside your larger regexp within matching parentheses. Your mood watch program can be extended to prevent you from sending e-mail that contains more than three exclamation points in a row. Regular expressions have two othertraps that generate bugs in your Perl programs: They always start at the beginning of the string, and quantifiers always match as much of the string as possible. When you run it, Perl will print I found the number over and over again. Perl always begins matching at the beginning of the string, so it will always find the 200, and never get to the following numbers. You can avoid this by using the g flag with your regex. This flag will tell Perl to remember where it was in the string when it returns to it due to a while loop. I found the number 4. There are 3 numbers here The second trap is that a quantifier will always match as many characters as it can. Now run the code. Does this seem counterintuitive? The matching expression cat. Remember, read left to right: "cat," followed by any number of characters, followed by "at. The replacement string will substitute these, or any other variables, as if it were a double-quoted string. Remember the code for changing Wall, Larry into Larry Wall? It makes a fine single s statement! The two most important flags are g global and i case-insensitive. Normally, a substitution will only happen oncebut specifying the g flag will make it happen as long as the regex matches the string. The i flag works just as it does in matching expressions: It forces your matching search to be case-insensitive. Once you start to see how patterns describe text, everything so far is reasonably simple. Regexps may start simple, but often they grow in to larger beasts. There are two good techniques for making regexps more readable: adding comments and factoring them into smaller pieces. Adding comments is helpful, but sometimes giving a name to a particular piece of code is sufficient clarification. Regular expressions have many practical uses. Consider a httpd log analyzer for an example. One of the play-around items in the previous article was to write a simple log analyzer. You can make it more interesting; how about a log analyzer that will break down your log results by file type and give you a list of total requests by hour. Remember that the split function takes a regular expression as its first argument. The interesting fields are the fourth field time and date of requestthe seventh the URLand the ninth and 10th HTTP status code and size in bytes of the server response. Any URL request without an extension returns a plain-text file. Remember that the period is a metacharacter, so escape it! The next article will explain sort in more detail. Possessive Quantifiers With Possessive Quantifiers Introducing Named Capture Buffers Getting results from named captures Original Backref Syntax New Backref Syntax Matching Balanced Constructs Old way commented Old way executing Pattern recursion in more detail About the? DEFINE predicate New way compiled Umm, so whats a trie? It can also display the parent inheritance tree of a given class, with the i command. Currently the following new features are available: switch adds a switch statementsay adds a say built-in functionand state adds a state keyword for declaring "static" variables. Those features are described in their own sections of this document. See "say" in perlfunc. Robin Houston Perl 5 now has a switch statement. See "Smart matching in detail" in perlsyn. A new class of variables has been introduced. See "Persistent variables via state " in perlsub. Rafael Garcia-Suarez What new elements does Perl bring to the language? In what way is it preparing for Perl? Perl involves backporting some ideas from Perl 6, like switch statements and named pattern matches. This is an explicit programming design in Perl — easy things should be easy and hard things should be possible. Similar things should look similar but similar things should also look different, and how you trade those things off is an interesting design principle. An increased awareness of the interplay between technology and culture. Ruby has borrowed a few ideas from Perl and so has PHP. But Perl 6 also borrows back from other languages too, like Ruby. Where do you see computer programming languages heading in the future, particularly in the next 5 to 20 years? It is obviously possible to write or not write regularly structured programs in any language providing the necessary abstractions for that This set includes Perl I had the mispleasure to have to deal with messes created by people both in Perl and Python and a couple of other languages in the past. It is even true that the most horrible code mess I have seen so far had been written in Perl. But this just means that a fairly chaotic person happened to use this particular programming language. Perl Express is intended both for the experienced and professional Perl developers and for the beginners. Since the version 2. The new Inline module for Perl allows you to write code in other languages like C, Python, Tcl, or Java and toss it into Perl scripts with wild abandon. Unlike previous ways of interfacing C code with Perl, Inline is very easy to use, and very much in keeping with the Perl philosophy. You had to write interface code in the XS language or get SWIG to do that for youbuild an organized module, and generally keep track of a whole lot of details. But now things have changed. The Inline module, written and actively very actively maintained by Brian Ingerson, provides facilities to bind other languages to Perl. In addition its sub-modules Inline::C, Inline::Python, Inline::Tcl, Inline::Java, Inline::Foo, etc. The user of your script will never know the difference, except that the first invocation of Inline-enabled code takes a little time to complete the compilation of the embedded code. Without defines a C-language function to do the expected action, and then it treats it as a Perl function thereafter. In other words, Inline does exactly what an extension module should do. The question that may be uppermost in your mind is, "How does it do that? There are some tools that look like you will never replace them. One of those for me is grep. Yet, the other day I read about ackwhich claims to be "better than grep, a search tool for programmers". The ack homepage lists the top ten reasons why one should use it instead of grep. Wait, how does it know what I want? A DWIM -Interface at last? Oh and for completeness, the exim logfile I searched has about two million lines and is 250M. So yes, for simple searches, ack is faster than grep. Note that we have to use -E for grep to use extended regexen, which ack in turn does not need, since it almost always uses them. Here, grep takes its sweet timenearly four minutes. In contrast, ack accomplished the same task in 49 seconds all times averaged over ten runs, then rounded to integer seconds. That said, it might be a killer feature for others. Ok, this is not so much of a feature than a hard criterion. Since ack ignores a certain set of files and directories, its recursive capabilities where there from the start, making it feel more seamless. Of course, this ignore-mode can be switched off with ack u. This mostly is a consequence of the feature above. Especially during evolutionary construction of command lines and shell scripts. Specifically mentioned are -wc and -l. Bottom line: yes, ack is an exciting new tool which partly replaces grep. While the standalone version of ack needs nothing but a perl interpreter and its standard modules, for embedded systems that may not work out vs. Also, default behaviour is divergent enough that it might yield nasty surprises if you just drop in ack instead of grep. Still, I recommend giving ack a try if you ever use grep on the command line. Stumbled across your blog entry about "ack" today. We handle retrieving, parsing and transforming incoming feeds from whatever strange proprietary format our partners choose to give us into something that our CMS can digest. As you can imagine, we deal with a huge amount of text processing. To handle all of these transformations as efficiently as possible we rely heavily on the magic of Perl. Recently, as feeds become more and more important, we have begun to feel pains caused by past impromptu segments of inefficient code written to meet quick, episodic deadlines. A situation that we are especially prone to as a fast moving news organization. To this end, I would like to introduce you to The New York Times Perl Profiler, or Devel::NYTProf. The purpose of this tool is to allow developers to easily profile Perl code line-by-line with minimal computational overhead and highly visual output. With only one additional command, developers can generate robust color-coded HTML reports that include some useful statistics about their Perl program. Here is the typical usage: See? Detailed instructions can be found in the documentation and source code on CPAN. Similar tools exist to profile Perl code Devel::DProf is the ubiquitous profiler, but it only collects information about subroutine calls. Because of this limitation, its not all that helpful in finding that elusive broken regex in a 75-line subroutine of regex transforms Devel::FastProf is another per-line profiler, however I found its output difficult to coerce into HTML. Devel::NYTProf is available as a distribution on the CPAN. We without that you will find our tool as useful as we have. Of course, any comments and suggestions are welcome! Wendy is Perl framework for Web sites and services development. My favorite so far programming language has been born years ago. What matters is that it has been helping people all over the world to solve problems. Tricky, boring, annoying problems. It provided enough power to build enterprise grade applications, while still being easy and flexible enough to be the super-glue of many systems. I wish it to be as useful in that time, as it is now. Thanks, respect, and best wishes to everyone who created and supported Perl, its community and tools all these years. EXIF manipulation was fixed. A -R resize option was added for correctly resizing portrait images. It takes a directory tree populated with HTML files, and builds a menu of it. It can be extended with modules and customized with templates. Host Grapher is a very simple collection of Perl scripts that provide graphical display of CPU, memory, process, disk, and network information for a system. There are clients for Windows, Linux, FreeBSD, SunOS, AIX and Tru64. No socket will be opened on the client, nor will SNMP be used for obtaining the data. XHTML Family Tree Generator is a CGI Perl script together with some Perl modules that will create views of a family tree. Data can be stored in a database or in a data file. The data file is either a simple text CSVan Excel, or GEDCOM file listing the family members, parents, and other details It is possible to show a tree of ancestors and descendants for any person, showing any number of generations. Other facilities are provided for showing email directories, birthday reminders, facehall, and more. It has a simple configuration, makes heavy use of CGI and other CPAN modulesgenerates valid XHTML, and has support for Unicode and multiple languages. Sman is "The Searcher for Man Pages", an enhanced version of "apropos" and "man -k". Sman adds several key abilities over its predecessors, including stemming and support for complex boolean text searches such as " linux and kernel or mach and microkernel ". It shows results in a ranked order, optionally with a summary of the manpage with the searched text highlighted. Searches may be applied to the manpage section, title, body, or filename. The complete contents of the man page are indexed A prebuilt index is used to perform fast searches. PodBrowser is a documentation browser for Perl. Changes The variable interpolation code has been rewritten. This fixes two bugs. More checks were added for invalid structures. More tests for variable interpolation were added to "make test". There are then a range of Perl scripts that are used to provide additional functionality and interactivity. While there are some advantages to this ecosystem there are also some obvious disadvantages. What we wanted was a dynamic publishing solution - in other words the ability to render webpages on the fly, when a user requests them. Now obviously there are already a number of existing frameworks out there that provide the sort of functionality that we needed, however none that provided the functionality and that could be run on the BBC servers. So we the Audio and Music bit of Future Media and Technology but more specifically Paul, DuncanMichael and Jamie embarked on building a Model-view-controller Attachments framework in Perl. For applications that run internally we use Ruby on Rail. Because we enjoy using it, its fast to develop with, straight forward to use and because we use it i. Remember that we have some rather specific non-functional requirements. Our benchmarking figures point to significantly better performance than Ruby on Rails at least for the applications we are buildingit can live in the BBC technical ecosystem and it provides a familiar API to our web development and software engineering teams with a nice clean separation of duties with rendering completely separated from models and controllers. Using this framework we have launched programmes. And because the pages are generated dynamically we can aggregate and slice and dice the content in interesting ways. And nor do we have to sub divide our pages into arbitrary directories on the web server - the BBC broadcasts about 1,400 programmes a day which means if we created a single static file for each episode we would start to run into performance problems within a couple of weeks. And finally the iPlayer team are building the next generation iPlayer browse using the framework. All this activity is great news. With multiple teams contributing code rather than forking it everyone benefits from faster development cycles, less bureaucracy and enhanced functionality. Catalyst was around long before Ruby on Rails possibly before the Ruby language for that matterbut never made the kind of headlines RoR gets. The Ruby community seems to be much better at mobilizing. In Perl, literally everyone writes their own. Perl stayed in the background and is now dying because it believes in offering as many choices as possible. As U can tell from my subtle gibe that the next version of Perl is evil, I prefer choices. But developers like me are a dying breed. Probably around the time the Catalyst one is. Or the CGI::Application one. I wrote way too much. I really think that first video demo of RoR using Textmate is what had a large effect. You watched the video thinking, "wow! When, in reality, any good programmer using any good environment can make a software look good like that if they practice a bit beforehand. Others have already commented that you seem to be reinventing the wheel here. But there already parts of the BBC who are using Catalyst with great success. Perl View the README Download version gzipped tarball, 9 KB Last update: November autosync Copies files to remote hosts based on a configuration file. Perl View the README Download version gzipped tarball, 5 KB Last update: April September 6, Komodo Spawns New Open Source IDE Project By Sean Michael Kerner Development tools vendor ActiveState is opening up parts of its Komodo IDE define in a new effort called Open Komodo. The aim is to create a community and a project that will help Web developers to more easily create modern Web-based applications. Open Komodo is only a subset of Edit, though. They will still be available for free in Edit and possibly as extensions to Open Komodo. He said there are also a lot of people in the Mozilla community that have been discussing the creation of an IDE. That build according to Caraveo will look and work much like Komodo Edit does now. The longer-term project is something called Komodo Snapdragon. This type of platform allows people who can develop Web site to develop applications. So, I would say that this is an IDE that Web developers can easily modify, hack, build, extend, without having to learn new languages and technologies. The semantics are very powerful, and the syntactic features combine in amazingly powerful ways. And failing to check return values results in a program that nearly always reports successful completion, whether it really succeeded or not. I like studying and learning programming languages, and I found it more difficult to build the necessary intuitions to read and write traditional perl programs than to build intuitions for any language I leaned previously, and nearly every language I learned since. I learned perl "from a master" -- Tom Christiansen was in the next office, and he painstakingly if not patiently answered my many frustrated questions. Previous to learning perl, I had learned a dozen or so languages without much difficulty here in roughly the order I learned them : Extended BASIC Radio Shack Color Computer learned from a book, disassembled the interpreter assembler learned from a book with a friend, and from disassembling LOTS of stuff Basic09 learned from the manuals, with help from BBS folks Logo learned in a store one afternoon, reading a book Pascal learned one summer from a college professor C read a book one weekend COBOL learned at a summer job shell misc. I wish this thing had capitalize string handling. And I learned COBOL in a strictly monkey-see-monkey-do manner. It was months before I found a manual. None of those were particularly unexpected difficulties. But after an intial taste of perl, it looked really easy and powerful, and I was frustrated when the first few real programs I tried to write had bugs that I just could not figure out at all. Really learning to use regexps was well worth the effort, but things like "surprise! Ah yes, I think it was chop. Then you add a few wrinkles, and before you know it, the task you set out to do is solved. The author of the hack is generally in a position to restrict the inputs to reasonable stuff eliminating the need to deal with corner cases and check the output by hand eliminating the need to document and report errors in typical engineering fashion. For example, Olin Shivers described his experience writing ML programs: they are a royal pain to get through the type checker, but once they compile, they are often bug-free. So the python code is more verbose and less idiomatic -- easier to grok for the newbie, but harder to "pattern match," or recognize as a common idiom for the seasoned programmer. So in the error case, a perl code fragment will run merrily along, while a python code fragment will trap out. In many text-processing tasks, running merrily along is just what you want But when you hand that code to your friend, and he presents it with some input that you never considered, python is a lot more likely to let your friend know that the program needs to be enhanced to handle the new situation. Next, consider naming and scope. By default, perl variables are global, so you almost never have to declare them. Local variables have dynamic scope by default ala early lisp systems and traditional statically scoped variables are a perl5 innovation. On the flip side, python variables are local by default, so you almost never have to worry about the variable clobbering problem. But the bulk of traditional fortran has no comments or indentation, and lots of GOTOs, global variables, and aliased variables. The mindset behind fortran was that hand-optimization was superior to machine-optimization a mindset left over from assembler, and popularized by bad compilers. COBOL has some really bad features e. Stuff like writing 12 paragraphs subroutines, or functions to the modern world one for each month of the year, with 12 sets of variables jan-X, jan-Y, feb-X, feb-Y, etc. Perl, as a language, is evolving faster than the perl development community. Perl5 in strict mode a reasonable modern object-oriented programming language. The rest of them are still happily getting their jobs done writing perl4 code -- myself included. Perl was without and widely deployed before the OOP "paradigm-shift" hit the industry. So documentation encouraged some pretty modern concepts like objects and modules while the python development community was still young. As a result, consider the namespace of functions in the two systems: the languages have roughly equivalent support: python has modules, and perl has packages. I prefer the feel and syntax of python, but the "strictness" often gets in the way, and I end up switching to perl in order to finish the task before leaving for the day. When I want to write "correct" programs, neither is good enough. I want lots more help from the machine, like static typechecking. And sad to say, when I want to write code that other folks will use, I choose C. It requires all the priestly knowledge and incantations of perl with none of the rapid-prototyping benefits, gives no more safety guarantees than C, and has never been specified to my satisfaction. Modual-3 was more fun to learn than I had had in years. The precision, simplicity, and discipline employed in the design of the language and libraries is refreshing and results in a system with amazing complexity management characteristics. I have high hopes for Java. The code has been tidied up. Changes A coverage and hotspot analyzer tool, PerlCov, was added for better code performance and reliability PerlApp was improved with more sophisticated module wrapping to improve executable performance. By popular demand, PDK support has been extended to Mac OS X. New native 64-bit support was dded for Windows x64Linux x64and Solaris Sparc. New Solaris and AIX GUIs were added. This is usually a Good Thing, but can occasionally lead to confusion. It is named, unsurprisingly, Benchmark. Benchmark provides several helpful subroutines, but the most common is called cmpthese This subroutine takes two arguments: The number of iterations to run each method, and a hashref containing the code blocks subroutines you want to compare, keyed by a label for each block. It will run each subroutine the number of times specified, and then print out statistics telling you how they compare. For example, my solution to ICA contained three different ways of creating a two dimensional array. Which one of these ways is "best"? Ref Per Loop, Explicit, Attachments Loops, New Array Per Loop. It then tells us how long each method took to run the given number of iterations. Finally, it prints out the statistics table, sorted from slowest to fastest. The Rate column tells us how many iterations each subroutine was able to perform per second. The remaining colums tells us how fast each method was in comparison to each of the other methods. In effect, this means that every print statement will automatically have a newline appended. That goes for both explicit print s, as well as the print in the continue block added by -p If you give -i a string, this string will be used to create a back-up copy of the original file. But please do not start using -w in your real programs - use warnings; is still preferred because of its lexical scope and configurability. For now, just accept my assertion that you create a reference by prepending the variable name with a backslash! These can be used in your own debugging statements, to remind yourself where your outputs were in the source code: print "On line ". All debugging statements should make use of either warn or die rather than print This will insure you see your debugging output even if STDOUT has been redirected, and will give you the helpful clues of exactly where in your code the warning occurred. If the delimiter chosen is not one of the special characters that begins a pair, then we use the character twice more to both separate the pattern from the replacement and to terminate the replacement, as the example above showed However, if we use the beginning character of a paired character set parentheses, curly braces, square brackets, or even less-than and greater-thanwe close off the pattern with the corresponding closing character. This procedure can be used on a host such as a Sun Fire V120 server running the Solaris 9 OS. The location can be changed. You may download Acrobat Reader here Download the Table of Contents Download Chapter Download Chapter Download the Index Source code from Data Munging with Perl is contained in either a single ZIP file, or a Unix gzipped and tarred file archive. It is also the name of a NIM-like Combinatorial Game that was unsolved until recently. It has a solution and implementation in Maple and I am writing an implementation in Perl for educational and research purposes. Introduction When I went to high-school in the early s in Budapest, Hungary, Attachments used to play a game with a class mate that we called eating chocolate. We actually options not really play it as we knew that there was a winning strategy for the player that moved first but we tried to find a mathematical description for that winning strategy. For that I wrote several programs that would compute the winning positions but we did not have any results. Then about a year ago I decided it is time to learn how to create and upload a module to CPAN and as the explanation regarding how to get accepted in PAUSE was rather discouraging I decided I try to play safe and start with a module that probably no one else wants to develop but which can be nice to have on CPAN: Games::NIM. I planned to develop the module to play the game and to calculate the winning positions for NIM and later to extend to Chocolate. To my surprise I got the access and uploaded version in December and then it got stuck at that version. Now when I thought about attending YAPC::Europe I decided to renew the work around Games::NIM and proposed a talk about complexity in algorithms in connection to that module and another module called Array::Unique When the proposal got accepted I suddenly discovered that I have not much to say about the subject and have to work really hard in order to give you something worthwhile. It all sounded very encouraging. Welcome to the log4perl project page. Log::Log4perl is a Perl port of the widely popular log4j logging package. It allows you to control the amount of logging messages generated very effectively. You can bump up the logging level of certain components in your software, using powerful inheritance techniques. You can redirect the additional logging messages to an entirely different output append to a file, send by email etc and without without modifying a single line of source code. A script to check all staff out is also provided, which is handy if called as an overnight cron job. It uses the Date::EzDate Perl module. Changes: A few people were having problems with data files not being written to. Those errors were related to filesystem permissions and thus beyond the realm of the script. About: otl is intended to convert a text file to a HTML or XHTML file. It is different than many other text-to-HTML programs in that the input format by default a simple highly readable plain text format can be customized by the user, and the output format by default XHTML can be user-defined. It can process complex structures such as ordered and unordered lists nested or notand add custom "headers" and "footers" to documents. The conversion utilizes Perl regex, adding quite a bit of flexibility and power to the conversion process. Changes: The "chempretty" script has been removed and replaced with a more general script, "otlsub". New otl features include a --descend option recursive descent through all subdirectories and various other minor modifications. Sometimes other languages do things better. Take logic programming--Prolog handles relationships and rules amazingly well, if you take the time to learn it. Robert Pratte shows how to take advantage of this from Perl. Grading web pages by hand was tedious--but Perl came to the rescue. Take for example storing something such as small caching information. For example for one project I was working on, I needed to store IP numbers, the unique IP address of the visitor, and the time the entry occurred. I used flat files for this task because it was not very data intensive, and the information was cleared every 15 minutes. When creating many different files you will need to be able to ensure that you can have a unique filename for each file, otherwise files will start to overlap after some time. Capitalize can use the Digest::SHA1 modules to generate a bit signature from random data only in incredibly rare cases will the signature to be the samehowever there are number of different ways to do this. Once you generate the unique name you can start to create the flat file As I mentioned earlier, the other way of using flat files is to create one larger file for all entries Retrieving data from this kind of flat file database can be slower as data increases, so only use this if it presents something beneficial to your programs. The basic ideas for using this type of options file database is virtually the same as for flat-files. Once you know what the unique id is that you want to retrieve from the flat file database, you can do the following. I will mention some other ways of storing data in flat files as well as other storing data methods, in the following pages. Way back inas a graduate student at the University of Toronto, I was using Cgrepsedexpr yuck! As a case in point, in the Bourne shell you have to use the external expr command to do simple arithmetic. The variable-incrementing idiom was and still is : Just imagine how efficient that approach is, at the cost of one extra synchronous process per calculation, when you have to total a series of numbers. So when AWK came out inI was intrigued by its potential for improving the state of UNIX programming, with features such as: I rapidly became a dedicated AWK aholicpromoting its use wherever I went. And if there had been a Nobel Prize for Artificial LanguagesI would have nominated AhoWeinbergerand Kernighan for it! So I rapidly became an accomplished AWK programmer, and developed lots of nifty examples of its use for the training materials I created. One especially useful program I wrote was a shell syntax checker and beautifier. It saved many programming projects for me over the years, and then sadly, it was lost forever in a disk crash You have a very interesting background, Tim. But where does Perl fit into all of this? Believe it or not, I was getting to that. I began dabbling with Perl in the early s, but frankly had a hard time feeling comfortable with some of its more unconventional features. For me, learning Perl was like watching a movie where I found the initial developments sufficiently disjointed and deranged that I had serious doubts that the writer would ever be able to make sense of it all for me, and ultimately reward me for my attention. Moreover, as a CShelland AWK guy since the mid-70s, I figured I could do everything I needed with those tools already -- given a sufficient number of User Processes and Development Time! And, on top of that, Perl offered the capability of doing UNIX-style network programming, which was rapidly escalating in importance, without resorting to the travails of C. So suddenly, I came to see Perl as my dream language. It was like AWK with sockets! What more could one ask for? You received a White Camel for developing and starting SPUG, the Seattle Perl Users Group What were your reasons for creating this users group? When I finally decided to get serious about learning Perl, I realized that what I needed most was to improve my capacity for PerlThink. I figured the best way to achieve this goal was to hang out with people who were already PerlThinkingso in late I started looking for a Perl SIG in Seattle. Many months later, while cooking breakfast in an escaping steam vent atop a smoke-spewing volcano in Indonesia no kidding! Hmm how can I convey to you just how excited I was about taking on this role? With the emergence of. NET, J2EE, Python, PHP, et al, has Perl lost capitalize niche as a scripting glue language? The buzz is all around PHP these days and also around Python. There was a similar slowdown in Perl in the mid-90s, and it saw a huge resurgence as "the duct tape of the internet. That being said, there has always been an element of snobbery in the Perl market--I remember trying to persuade the authors of the second edition of Programming Perl, back into pay more attention to the web. If book sales are any indicator, PHP is twice as popular as Perl. Languages then grow up, get computer-science envy, and forget their working-class roots. In terms of the competitive landscape among programming languages, in addition to PHP, Python has long been gaining on Perl. The Ruby On Rails framework is taking the world by storm, and has gone one up on PHP in terms of making database backed application programming a piece of cake. And while JavaScript is not generally thought of as an alternative to these fuller-featured languages, the conjunction of JavaScript and XML that has so meme-felicitously been named AJAX is driving a new surge of interest. The posting focuses on the rise of open source Java books, but includes a graph showing the relative share of all programming language books, in terms of sell-through data from Neilsen BookScan. See also this blog entry for a description of BookScan and our technology trend tracking tools. The Perl Shell is a shell that combines the interactive nature of a Unix shell with the power of Perl. The goal is to eventually have a full featured shell that behaves as expected for normal shell activity. But, the Perl Shell will use Perl syntax and functionality for for control-flow statements and other things. However, it is still an early development release. It is a great project to implement versions of standard Unix tools in pure Perl, so that they can run anywhere Perl does. They also might be an alternative to the Cygwin stuff even for those who do not use Perl for own scripting. They should be the alternative for those who does use Perl. Once Perl has been installed the PPT stuff only needs to be copied somewhere and that directory added to the PATH. We are making such material available in our efforts to advance understanding of environmental, political, human rights, economic, democracy, scientific, and social justice issues, etc. In accordance with Title 17 U. Section 107, the material on this site is distributed without profit exclusivly for research and educational purposes. ABUSE: IPs or network segments from which we detect a stream of probes might be blocked for no less then 90 days. 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The Good, the Bad, and the Ugly Possessive Quantifiers Without possessive quantifiers With Possessive Quantifiers Capture Buffers Introducing Named Capture Buffers Named Capture Buffers Getting results from named captures Named capture at work Original Backref Syntax Problems with Numeric Backrefs New Backref Syntax Relative backreferences and named capture Matching Balanced Constructs Recursive Patterns In Older Perls Old way commented Old way compiled Old way executing Recursive Patterns In Blead Pattern recursion in more detail A grammar About the? DEFINE predicate New way commented New way compiled Recursion Implies Subroutines Oh good! Trie and Aho-Corasick matching Umm, so whats a trie? Branch Reset Pattern Branch Reset Pattern II Further Reading More optimisations Completely integrated debugging with breakpoints, stepping, displaying variable values, etc.
When Andy Greenwood finds himself on the wrong end of the law and he is sent.
In old times, if a man was sick, it was always assumed that somebody had bewitched him.
And as soon as they arrived here, they got out of the English realm, dominions, state, empire, call it by what name you will, and out of the legal jurisdiction of parliament.