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• what to learn & practice to be a programmer (not for Job) [closed]

  - by Hanan N.

  I want to be able to write programs (tools) for my own needs, and I want to tell the computer what to do, not to be strict to what other's told it to do. I have a good knowledge of Linux & Windows, I am also have a bit of Python in my head, but I think that I need some guidance on what languages or practices to invest my time into in order to be able to tell the computer what to do. I know there is a lot of posts similar to what I am asking here, but there is a big difference and so I have opened this thread. My goal isn't to work at a company, so I don't need to learn how to work as a team, I don't need to learn as much how to maintain my code nor how to write it nice for others to understand (I know it is important but not for me). I don't want to learn it as a profession, but as a serious hobby (you can call it hacking as long as you know what cracking means), my end goal is to be able to understand other's people code, and to write my own code with a lot of deep knowledge of the ins and outs of the computer system in order to gain from it as much as I can. So in essence my questions are: How can I understand, in depth, computers, in order to exploit them as much as I can? What should I learn? Are there any books that I should read? Is it possible to do this, or do I have to learn every aspect of programming?

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• Linux- passwordless ssh from system (root) script

  - by redmoskito

  What's the easiest way to have a system script (running as root) execute remote commands over ssh? I've written some scripts that execute commands remotely via ssh, and they work great when I run them as myself, as I've set up ssh-agent and keys for passwordless login. I'd like to call these when my laptop docks and undocks. I've been successful at running arbitrary scripts when docking/undocking, but since the ACPI event scripts run as root, trying to run my ssh script fails during authentication. I tried using sudo with the -u and -i flags to simulate running the script as my user, e.g.: sudo -u redmoskito -i /home/redmoskito/bin/remote_command which successfully finds my private key and tries to use it, but the ssh-agent credentials are still missing, so it still needs my passphrase.

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• Why doesn't this batch file work for me?

  - by asdfg

  The following batch file is not woking. @echo off python -c "print('echo text')" %TEMP%\test.bat call %TEMP%\test.bat Can anyone help me with this?. edit: I needed unix eval functionality in windows. I could not find a direct way though. So I redirected the eval string to a temporary batch file and executed it. The temporary batch file was successfully created but calling it did not work in the above case. I noticed that any command after the test.bat creation did not work.

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• Non-dynamic CMS [closed]

  - by user20457

  Some of the web sites I visit every day (news, sports, etc..), although the content changes very often (several times per day), the URLs always have .html extension, what makes me thing that the content has been generated once, and then published as a static page, rather than generated in every call, or even cached in memory. For example, the fictitious site "mysports.com" have a "futbol.html" page, and then yesterday Messi gets injured and they have another thing to put in that page, then I presume they post the new item in their CMS system, and automatically a publishing action is triggered aftewards that recreates "futbol.html" in a CDN with the new item and probably discard the oldest one. Then the ETag changes and clients will get the new page if they try to access it. (the site is fictitious but this is what I believe happened yesterday in the sports site I read) This would fit in the CQRS approach, and I presume they have a huge performance. I know lots of CMS (WP, Drupal, BlogEngine.net, DNN, etc...), but I have never seen any able of doing this, or at least, I was not aware this feautre. How are called those distributed CMS? Which are the most well known? Cheers.

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• Solaris 11 installed, no updates?

  - by Paul De Niro

  I was messing around with solaris and decided to give Solaris 11 a try so I downloaded it from the Oracle website. After installing the OS, I went into the package manager and did an update. It told me that there were to available updates! I find this hard to believe considering that it's running a vulnerable version of firefox and java, its own in-house software product! Many of the other software products that came with the default install are also out of date and vulnerable. Is this normal for an Oracle install, or did I do something wrong with the upgrade process? I typed "pkg update" at the prompt, and I noticed that it did call out to pkg.oracle.com looking for updates. I find it bizarre that there are no updates available for an OS that was released a couple months ago with vulnerable software...

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• What is the most concise, unambiguous syntax for operator associated methods (for overloading etc.) that doesn't pollute the namespace?

  - by Doug Treadwell

  Python tends to add double underscores before its built-in or overloadable operator methods, like __add(), whereas C++ requires declaring overloaded operators as operator + (Thing& thing) { /* code */ } for example. Personally I like the operator syntax because it seems to be more explicit and keeps these operator overloading methods separated from other methods without introducing weird prefix notation. What are your thoughts? Also, what about the case of built-in methods that are needed for the programming language to work properly? Is name mangling (like adding __ prefix or sys or something) the best solution here? What do you think about having another type of method declaration, like ... "system method" for lack of creativity at the moment. So there would be two kinds of declarations: int method_name() { ... } system int method_name() { ... } ... and the call would need to be different to distinguish between them. obj.method_name(); vs obj:method_name(); perhaps, assuming a language where : can be unambiguously used in this situation. obj.method_name() vs obj.(system method_name)() Sure, the latter is ugly, but the idea is to make the common case simple and system stuff should be kept out of the way. Maybe the Objective-C notation of method calls? [obj method_name]? Are there more alternatives? Please make suggestions.

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• multi-thread in mmorpg server

  - by jean

  For MMORPG, there is a tick function to update every object's state in a map. The function was triggered by a timer in fixed interval. So each map's update can be dispatch to different thread. At other side, server handle player incoming package have its own threads also: I/O threads. Generally, the handler of the corresponding incoming package run in I/O threads. So there is a problem: thread synchronization. I have consider two methods: Synchronize with mutex. I/O thread lock a mutex before execute handler function and map thread lock same mutex before it execute map's update. Execute all handler functions in map's thread, I/O thread only queue the incoming handler and let map thread to pop the queue then call handler function. These two have a disadvantage: delay. For method 1, if the map's tick function is running, then all clients' request need to waiting the lock release. For method 2, if map's tick function is running, all clients' request need to waiting for next tick to be handle. Of course, there is another method: add lock to functions that use data which will be accessed both in I/O thread & map thread. But this is hard to maintain and easy to goes incorrect. It needs carefully check all variables whether or not accessed by both two kinds thread. My problem is: is there better way to do this? Notice that I said map is logic concept means no interactions can happen between two map except transport. I/O thread means thread in 3rd part network lib which used to handle client request.

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• IOException opening RFCOMM on openSUSE

  - by Chief A-G

  I have a permissions problem on openSUSE with Bluetooth /dev/rfcomm0. I've written a small test application which opens /dev/rfcomm0 and sends a request message and retrieves a response message. At first my problem was a permission denied error on /dev/rfcomm0 until I added the user account to the dialup users group. Now I get a System.IO.IOException Interrupted system call error whenever I run the app. I can sudo my application and it runs fine. I'm not sure how and which permissions to set to get this work work under my normal user account.

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• How do I get the current date according to an NTP server without setting it locally?

  - by Zac B

  I want to get the current date and time according to a remote NTP server, using Linux. I don't want to change the local time as a result; I just want to get the remote date, adjusted for the local time zone, printed out. The date returned must comply with the following criteria: It needs to be reasonably accurate. It needs to be adjusted for the timezone on the local system making the request. It needs to be formatted in an easily-readable or interpretable way (standard date format, or seconds since epoch). What I've Tried: I can call ntpdate -q my.ntp.server and get the offset between the local time and the server's time, but that doesn't return the date according to the NTP server; it just returns the offset and the local date. Is there some easy way/command I can use to say: "Print out the date according to a given NTP server, adjusted for my current timezone"?

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• Run preseed commands as specific user / switching users

  - by pduersteler

  Beside the usual setup where I create a normal user foo, I want to run a few d-i preseed/late_command commands as that foo user. My initial thought was to simply call those commands with sudo, e.g: d-i preseed/late_command in-target echo "<pwd>" | sudo -Si <command>. This works for some sort of commands. However the problem is that some of the commands load up shell scripts which require to not be run with sudo. Issuing a su -c "<command>" would be an alternative, but su does not offer the possibility to read the password from stdin. Is it safe to jump around between the users using su (And if yes, how do I provide the stdin? and does it work or just result in a su: must be run from a terminal) or would this cause issues?

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• elastix cdr stop working

  - by dreddko

  CDR was working before 19 march. Unfortunately i dont remember what kind of changes i made to configuration, but this exactly not changes to CDR config. elastix 2.4.0 asterisk 11.7.0 mysql 5.0.95 elastix*CLI> cdr show status Call Detail Record (CDR) settings ---------------------------------- Logging: Disabled Mode: Simple /etc/asterisk/cdr.conf [general] enable=yes unanswered = yes /etc/asterisk/cdr_mysql.conf [global] hostname = localhost dbname=asteriskcdrdb password = *MYPASSWROD* user = asteriskcdruser userfield=1 ;port=3306 ;sock=/tmp/mysql.sock loguniqueid=yes mysql> SHOW GRANTS FOR 'asteriskcdruser'@'localhost'; +-----------------------------------------------------------------------------------------------+ | Grants for asteriskcdruser@localhost | +-----------------------------------------------------------------------------------------------+ | GRANT USAGE ON *.* TO 'asteriskcdruser'@'localhost' IDENTIFIED BY PASSWORD 'HASHHERE' | | GRANT ALL PRIVILEGES ON `asteriskcdrdb`.* TO 'asteriskcdruser'@'localhost' | +-----------------------------------------------------------------------------------------------+ 2 rows in set (0.00 sec)

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• Running multipul lines through a server.

  - by Kevin Roberson

  I am looking to buy numbers in bulk on DIDx.net. After I purchase the numbers in a particular area code, I want to forward those numbers to other numbers that are outside of that area code. This way it will be seen as a local call versus long distance. I have the customers but I don't have the system I need. I have read about Asterisk, VOIP, SIP, and BYOH. But I have no clue what will be the best system for me. Does anyone have any idea what my next step should be when it comes to hardware and software? Or what type of operating system I should use? I basically want to set up a system like GoogleVoice & Phonebooth.

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• determine the archetecture of a mac from the command line or script?

  - by Brian Postow

  I'm writing a shell script, and I need to know the archetecture, ie PPC or Intel. Back in the day, there was a program /bin/arch that told you, but my mac doesn't seem to have it... Is there an easy way I can do this? Grep for something in a logfile? call some other program that spits that out as a side effect? It would be nice to know what OS Version I'm running too, but that may not be necessary. thanks

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• Designing object oriented programming

  - by Pota Onasys

  Basically, I want to make api calls using an SDK I am writing. I have the following classes: Car CarData (stores input values needed to create a car like model, make, etc) Basically to create a car I do the following: [Car carWithData: cardata onSuccess: successHandler onError: errorHandler] that basically is a factory method that creates instance of Car after making an API call request and populating the new Car class with the response and passes that instance to the successHandler. So "Car" has the above static method to create that car, but also has non-static methods to edit, delete cars (which would make edit, delete API calls to the server) So when the Car create static method passes a new car to the successHandler by doing the following: successHandler([[Car alloc] initWithDictionary: dictionary) The success handler can go ahead and use that new car to do the following: [car update: cardata] [car delete] considering the new car object now has an ID for each car that it can pass to the update and delete API calls. My questions: Do I need a cardata object to store user inputs or can I store them in the car object that would also later store the response from all of the api calls? How can I improve this model? With regards to CarData, note that there might be different inputs for the different API calls. So create function might need to know model, make, etc, but find function might need to know the number of items to find, the limit, the start id, etc.

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• Is there an alternative to the term "calling object"?

  - by ybakos

  Let's suppose you've got a class defined (in pseudocode): class Puppy { // ... string sound = "Rawr!"; void bark() { print(sound); } } And say, given a Puppy instance, you call it's bark() method: Puppy p; p.bark(); Notice how bark() uses the member variable sound. In many contexts, I've seen folks describe sound as the member variable of the "calling object." My question is, what's a better term to use than "calling object?" To me, the object is not doing any calling. We know that member functions are in a way just functions with an implicit this or self parameter. I've come up with "receiving object," or "message recipient," which makes sense if you're down with the "messaging" paradigm. Do any of you happy hackers have a term that you like to use? I feel it should mean "the object upon which a method is called" and TOUWAMIC just doesn't cut it.

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• Multiple Windows Desktop areas for Full-Screen applications

  - by arootbeer

  Is it possible to run multiple instances of Windows Explorer within a single user session, or configure multiple desktops that are portions of a screen? I don't know the best way to describe what I want to achieve, but here's a picture of what I've got: I've got a 4 monitor setup, 3 portrait and one landscape, and I am normally running a number of RDP sessions, outlook, chrome, a development environment or two, so on and so forth. Most of these applications support full-screen views which mostly or completely hide the window borders, but on the Windows Desktop they take up a full monitor to do so. What I want to do is have 7 "desktops", "regions", call them what you will, each of which is, for the purposes of applications running in it, a "full screen" environment: I'm not tied to Windows Explorer for this, in case it helps - a different window manager that will support this functionality would be a perfectly acceptable answer.

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• Automated VLAN creation with residential Wireless devices

  - by Zephyr Pellerin

  We've got a few WRT devices from Linksys here, and the issue has arisen to deploy them in a relatively small environment, However, in the interest of manageability we'd like to be able to automatically VLAN (ideally NOT subnet) every user from one another. It seems obvious to me that the default firmware isn't capable of this - can OpenWRT/Tomato/DD-WRT support any sort of functionality such that new users are automatically VLANed or otherwise logically separated from other users? It seems like there's an easy IPtables or PF solution here, but I've been wrong before. (If that seemed a little ambiguous, heres an example) User 1 sends DHCP request to server, new VLAN (We'll call VLAN 1) is created, user is placed in that VLAN. Then, user 2 sends a DHCP request and is placed in VLAN 2 etc. etc.

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• Start ELEVATED script from within script

  - by Ulrich

  Hallo, I'm playing around with Powershell (relative NewBie) and I'm looking for the easiest way to call a Powershell script with elevated rights from within another script. I know of the runas verb for start-process which allows me to start a new script with a different account. My problem is, however, that under Vista (UAC active) every admin account has two access tokens, a normal privilege one and an elevated one. If I use the runas method, the second scripts gets started under the right account but with the non-elevated access token. Is there an easy way to control this? Thanks a lot for your help! Ulrich

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• AngularJS dealing with large data sets (Strategy)

  - by Brian

  I am working on developing a personal temperature logging viewer based on my rasppi curl'ing data into my web server's api. Temperatures are taken every 2 seconds and I can have several temperature sensors posting data. Needless to say I will have a lot of data to handle even within the scope of an hour. I have implemented a very simple paging api from the server so the server doesn't timeout and is currently only returning data in 1000 units per call, then paging through the data. I had the idea to intially show say the last 20 minutes of data from a sensor (or all sensors depending on user choices), then allowing the user to select other timeframes from which to show data. The issue comes in when you want to view all sensors or an extended time period (say 24 hours). Is there a best practice of handling this large amount of data? Would it be useful to load those first 20 minutes into the live view and then cache into local storage something like the last 24 hours? I haven't been able to find a decent idea of this in use yet even though there are a lot of ways to take this problem. I am just looking for some suggestions as to what might provide a good balance between good performance and not caching the entire data set on the client side (as beyond a week of data this might not be feasible).

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• Guidelines for creating referentially transparent callables

  - by max

  In some cases, I want to use referentially transparent callables while coding in Python. My goals are to help with handling concurrency, memoization, unit testing, and verification of code correctness. I want to write down clear rules for myself and other developers to follow that would ensure referential transparency. I don't mind that Python won't enforce any rules - we trust ourselves to follow them. Note that we never modify functions or methods in place (i.e., by hacking into the bytecode). Would the following make sense? A callable object c of class C will be referentially transparent if: Whenever the returned value of c(...) depends on any instance attributes, global variables, or disk files, such attributes, variables, and files must not change for the duration of the program execution; the only exception is that instance attributes may be changed during instance initialization. When c(...) is executed, no modifications to the program state occur that may affect the behavior of any object accessed through its "public interface" (as defined by us). If we don't put any restrictions on what "public interface" includes, then rule #2 becomes: When c(...) is executed, no objects are modified that are visible outside the scope of c.__call__. Note: I unsuccessfully tried to ask this question on SO, but I'm hoping it's more appropriate to this site.

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• Running multiple lines through a server.

  - by Kevin Roberson

  I am looking to buy numbers in bulk on DIDx.net. After I purchase the numbers in a particular area code, I want to forward those numbers to other numbers that are outside of that area code. This way it will be seen as a local call versus long distance. I have the customers but I don't have the system I need. I have read about Asterisk, VOIP, SIP, and BYOH. But I have no clue what will be the best system for me. Does anyone have any idea what my next step should be when it comes to hardware and software? Or what type of operating system I should use? I basically want to set up a system like GoogleVoice & Phonebooth.

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• Can I eventually consider myself a professional developer if I don't have a CS degree? [on hold]

  - by heltonbiker

  Question first, context later: If I am a dedicated, self-taught programmer, always seeking top-quality books AND READING THEM, while successfully applying all that new knowledge into my current work, could I call myself (and offer my work as) a PROFESSIONAL developer? How limiting (or how common) that is nowadays? I am afraid that, no matter how hard I study and practice, it could be too difficult to compete with "actual", college graduated developers, and potential employers might have doubts investing in an "undergraduated" person. Now, context: My former profession is from healthcare sector, then I studied mechanical engineering (quit in the middle), then I studied product design (master degree), and I ended up working (very happily) at an engineering company that manufactures medical devices. For more than two years now my main activity in this company is software development. The devices contain software, and we gave up hiring software development (domain knowledge needed, too much communication cost). My current company sees a lot of value in what I do, but I cannot afford the risk of depending on this single company for the rest of my life, you get it. But a lot of job offers require some minimal formal education, usually a CS degree. Fact is that I am sure this is my target profession, I don't plan to go to another area, it is a pleasure to dive into books that normal people would consider unreadable, but I'm 36 years old and can't see going back to college as a viable alternative.

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• Do you think Microsoft is finally on the right track with its Windows 7?

  - by Saif Bechan

  It has been a while now since Windows 7 has been released. So far I didn't hear of many major complaints about it. I can remember the time that Windows Vista hist the shelves. There were major complaints from both experts and just regular users. I do a lot of OS installs for just regular users. These are mostly family and friends, and sometimes there are some customers. Up till now I mostly still use Windows XP SP3, because it is stable and most people are familiar with it. I did Vista for some users but they always call me back with all sorts of questions and in the end I had to downgrade them to XP. Do you think it is safe now to recommend Windows 7 as a good operating system? Offcourse their hardware has to support it, but let's say that is the case. If you install Windows 7 a lot for people, what are the complaints about if you get them?

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• License compatibility question

  - by Ivaylo Slavov

  I have a question regarding software licenses. I plan to put a license to a framework that I have written. My intention is that the license should be open, in order to maintain a community. Also I want to control when a new version is released and which changes will be included. The license should allow the framework to be used with commercial products, therefore respecting their own license. I have done some quick research and I decided to double license my work under the Apache License 2.0 (ASL) and Eclipse Public License (EPL). My point is that the EPL will provide me the ability to control the release cycle as well as the contributions to the project and the Apache license will take care for any patents a 3rd party might want to use in a derived work. Also both are open licenses. My question is related to the GLP and LGPL licenses. If I have the above licenses to my framework, will it be possible and legal, for someone to create a derived work of my framework, that is also a derived work of, or links a library that is under the LGPL license? Thanks in advance. EDIT: To be clear I will explain how I expect things to work. The framework will define some common API for certain functionalities as well as a Wrapper class that will invoke an implementation of that API. The Wrapper will be part of the framework, but it will internally call the actual implementation. This implementation should be in a separate library, and such libraries I would like to be developed and maintained by community. Surely the community will have to access the framework but I want to limit changes to the framework by the community but I want to provide freedom for any API implementation (a derived work of the framework). The framework will enable flexible configuration mechanisms that will tell which implementation of an API will be used.

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• Can someone explain the (reasons for the) implications of colum vs row major in multiplication/concatenation?

  - by sebf

  I am trying to learn how to construct view and projection matrices, and keep reaching difficulties in my implementation owing to my confusion about the two standards for matrices. I know how to multiply a matrix, and I can see that transposing before multiplication would completely change the result, hence the need to multiply in a different order. What I don't understand though is whats meant by only 'notational convention' - from the articles here and here the authors appear to assert that it makes no difference to how the matrix is stored, or transferred to the GPU, but on the second page that matrix is clearly not equivalent to how it would be laid out in memory for row-major; and if I look at a populated matrix in my program I see the translation components occupying the 4th, 8th and 12th elements. Given that: "post-multiplying with column-major matrices produces the same result as pre-multiplying with row-major matrices. " Why in the following snippet of code: Matrix4 r = t3 * t2 * t1; Matrix4 r2 = t1.Transpose() * t2.Transpose() * t3.Transpose(); Does r != r2 and why does pos3 != pos for: Vector4 pos = wvpM * new Vector4(0f, 15f, 15f, 1); Vector4 pos3 = wvpM.Transpose() * new Vector4(0f, 15f, 15f, 1); Does the multiplication process change depending on whether the matrices are row or column major, or is it just the order (for an equivalent effect?) One thing that isn't helping this become any clearer, is that when provided to DirectX, my column major WVP matrix is used successfully to transform vertices with the HLSL call: mul(vector,matrix) which should result in the vector being treated as row-major, so how can the column major matrix provided by my math library work?

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