Performance difference between find and find2perl? - linux

Is there a performance difference between find and find2perl? I work for a hosting company and I was told that our admins prefer us to use find2perl over find. Supposedly this is because find is heavier on resource usage than find2perl? Does anyone know if this is true and if so, could you please explain why?

find2perl translates the find into a perl script supposedly for later use (in perl). The man page states that is "typically faster than running find itself" and I guess that is why your sysadmins tell you to use it, or maybe they are simply perl fans.

Related

Find valid slaveaddresses or number of slaveaddresses in minimalmodbus

The documentation doesn't offer a way to do this and as far as i know a bus is not designed to do this. But maybe there is a kind of answer one can get from the devices without disturbing anything to determine which ones are there?
Searching a lot did not yield any answer besides "try every possible address and see if you get an answer"
Given that professional software also seems to use this aproach, it is probably the only way.

P4: how to find files in a case insensitive manner?

Say a file is known to P4 as Foo.cpp
p4 files -e -m 100 //XXX/YYY/...foo.cpp*
(note the lower case f) can't find it. Has anyone overcome this issue?
EDIT: the place I am running the command from does not have a local p4 checkout so going through the file system is not an option here.
If you are able, I would highly recommend going through the trouble (thanks to Linux-dependency hell) of installing P4Search. It will give you the case-insensitive searching power you seek, but it will also save you hours and hours of time down the road.
http://www.perforce.com/perforce/r14.1/user/p4searchnotes.txt
You could use the Perforce Broker to rewrite the command, but this would only be practical if all of your files started with an upper case letter.
Some examples of using the broker to rewrite commands are here:
http://www.perforce.com/blog/120727/customising-perforce-using-p4broker-rewrite-command
The simplest long term solution may be to move to a case insensitive server, but note that this is not a trivial process.
If this is something you want to do, I strongly recommend you contact 'support#perforce.com' for advice and more information.
You might also find this KB article helpful:
http://answers.perforce.com/articles/KB/3081
Hope this helps,
Jen.

Linux utility to know command for a particular task

In my initial days of using linux I usually had to search google to know the command for
doing a particular task. Once I have the command name, i can view its usage using man command-name.
Similarly I was thinking of some utility which can tell the command to do a particular task if the task to be done is specified as an argument and opens the man page for that command
e.g:
findUtilty "find all files in a directory"
output:
ls
find
I want to know if some utility of that kind exists, if so it will be very handy especially for newbies.
If not then i may like to implement it.
thanx,
Not as nice as you are asking about, but
apropos <keyword>
and
man -k <keyword>
can be very useful.
Parsing natural language is hard because there are thousands of ways to rephrase one sentence. Google does it best as far as I know. So, there is no such tool. There are handy and practical manuals that makes it easy to find the right tool for the job. Also, there is a huge community behind core-utils (and linux in general), so try both forums and IRC. Often, the latter is the fastest. And people tend to parse natural language as expected :)
apropos will do something like you suggest.
I guess it is: List of Unix utilities # Wikipedia
on Debian (and presumably derived systems) this is also useful:
sudo apt-cache search <keyword>
Few years ago NetBSD decided to rewrite its apropos. The new implementation does a full text search with results ranked in order of relevance. It comes close to what you have asked. See the output here
https://man-k.org/search?q=find+all+files+in+directory

Vulnerability & Exploit Case Studies

I understand the general idea of how vulnerabilities are exploited. Buffer overflows and stuff like that, but I guess I don't REALLY get it.
Are there useful sources of information that explain this area well? Maybe case studies about how particular vulnerabilities were exploited?
Even more interesting would be how projects you have worked on suffered from these kinds of issues.
I'm not trying to learn about currently existing vulnerabilities that I could exploit. I'm trying to get a feel for how this area could have an impact on any projects I may work on.
iss.net has articles on different examples of exploits, mainly explaining how to secure your system.
The corelancoder tutorial! A must read
https://www.corelan.be/index.php/2009/07/19/exploit-writing-tutorial-part-1-stack-based-overflows/
Part 1 is a single BOF on windows, ... , Part 12 is ROP. It is hard, but the first one can be done in a day or two, and it should give you a real feeling on which difficulties one finds when writing an exploit, and on which countermeasures are useless/useful.
The problem with this area is that it is unclear until you try out something on your own, but that requires time. You could also check Metasploit to exploit problems directly (to have an idea of the impact) - you will find a list of exploit to fire to a target. If you need a target, use Metasploitable http://www.offensive-security.com/metasploit-unleashed/Requirements#Metasploitable
If you want practical examples of real life exploits, I totally recommend the book
"A Bug Hunter's Diary: A Guided Tour Through the Wilds of Software Security"
It's exactly what you want. It's full of case studies and real life examples of almost every type of exploits and it explains it from the finding to fully writing a working exploit.
Also there are some examples in the book "The shellcoders handbook" but it's not as comprehensive as "The bug hunter's diary" Also "The shellcoders handbook" is pretty big and I only use it as a reference when needed.
Also sometimes I keep reading exploits from "http://www.exploit-db.com" and it helped me a lot but keep in mind not everything can be taught so sometimes you will need to improvise based on what you have and what you can control it's hard at first but it will make you feel great when the exploit runs and you see that calc.exe :)
Of course corlan tutorials and other tutorials are a must to know the essentials but they only teach you the basic concepts and you have to see some real life exploits in action to really understand the possibilities.

Ethics of using a "fringe" language for your job? [closed]

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Closed 10 years ago.
Just want to ask for some opinions here. How do you feel about using a language (and/or framework) that isn't widely used in your location to write software for a company? For instance, I live in an area dominated by .NET, with the occasional PHP job. Let's say that I'm learning Python and decide to use it to write software for my job (I'm a "Team of One" so I can pretty much use anything I want).
Now their software is written in a language that pretty much nobody in the area uses or knows; if I were to leave the company, they'd basically have nobody to maintain/add to it unless they retain on me as a consultant. While that's really good for me, it seems a bit "crooked" - granted, that's how the business world works.
What are your thoughts?
I should mention that this is a very small company and I'm the only IT person, so I have full reign to choose our development platform. I'm not specifically using Python, but chose it as an example since my area is almost entirely .NET based; I don't care for .NET anymore though, which is why I don't want to consider using it. Also, the company is.. how shall we say... extremely frugal and wouldn't purchase the required resources for .NET (e.g. server licenses, SQL licenses, Visual Studio, components). I personally have an MSDN subscription but I can't use that for them.
Also FWIW there are people in the area who use the language I'm considering using (Ruby on Rails), but nowhere near as many people as .NET developers. It's not like I'm using something that only I know.
You may think that this approach is good for you. But in fact all this does is paint you in to a corner. The best way to get promotion - within an organisation is to make yourself unnecessary in your current position. That might seem like nonsense, but it is in fact true. Think of it like this, if it is essential to the company that you continue to maintain the python code you wrote for them, and they can't go to anyone else to get that skill, then they will continue to pay (maybe a little above market rates) to maintain that code.
If however, you write that code in .net where there is a plentiful supply in your area, then as the company expands and the code you've written proves successful, you will be able to hire people to maintain that code and you can move on to designing other systems. Or moving in to managing a team of .net coders - if that's your want.
Even if you want to leave, the best thing for your career is going to be to get the best possible reference. To do that, write them some code that is easy to maintain. Help them hire someone to replace you to maintain it. They will be grateful and recommend you as a consultant to their friends.
Code in something esoteric - for which there is little support in your area - and they will be saying to their friends on the golf course "no don't hire that guy, he wrote this system for us which does the job, but no one else can maintain it. We're stuck with him forever and now he's too busy to look after us properly!"
Do what's best for the business, not what might be of most interest to you - or appear that way on the face of it. You'll win out in the long run.
I think that you're responsible to decide on the language that's best suited for the job. That includes an objective evaluation of the merits of the language and framework, it includes your own personal skill with the language (since you're the one doing the work) and it includes maintainability by others. Only you and your company can decide how much importance to place on each of those.
For your own personal development, if your area is dominated by .net, why don't you want to get up to speed in that instead of Python?
From an ethical standpoint, I would not write something that could not easily be maintained by someone else.
A lot of responses seem to be a poor fit for the question. We're not talking about using an unapproved language in an environment with existing standards. We're talking about a situation where the poster is the entire IT and development department for his company.
It's certainly important to keep in mind availability of talent, but Ruby is hardly a fringe language these days. In an environment where there's only one developer, productivity is also a very important consideration. Being able to build and maintain software quickly and easily without a large team requires tools with different characteristics than a large team might require.
I think what's more important than whether to use Ruby or (something else) is to try to pick something as general-purpose as practical and use it for everything unless there's a really good reason to use something else. If you go with Ruby, stick with Ruby for your utility scripts, cron jobs and that little GUI app the boss wanted to automatically SMS the intern when he takes more than five minutes to bring him his coffee.
I think using python would be the right thing to do if it would meet the clients requirements, and save them money over the alternative. Whether or not there is a wide assortment of characters to work on the application down the road is irrelevant, unless they've specified this as a non-functional requirement.
As usual, using the best tool for the job at hand will serve you well.
It indeed is a bit crooked IF you use it only for that purpose.
However, if you use it because it IS the best solution, youre in the clear.
Also, they can just hire someone else who knows python.
My work ethics dont allow me to do something like this just to keep me in business.
My personal opinion is you should try where possible to respect the working practices of wherever you are - whether that's indentation style, naming convention, testing procedure or programming language.
If you feel strongly that a different language would be better suited for a certain task, then lobby to have it accepted (with the required re-training of others).
Purposefully leaving an app that no one else can maintain is very bad professional conduct, IMO.
We recently had a bad hire at my shop and he decided out of the blue he was going to use Perl instead of any version of .NET to do some simple reporting stuff (That could have just as easily been done in .NET). It was atrocious. I would suggest using the platform as specified and clearing any deviation with the people who run the joint...
Plenty of answers have touched on this, but here's my take based on production application support.
My company had a startup phase where code hustlers whipped up solutions in whatever the personal preference or flavor of the week was. Bad for maintainability and supportability.
Making a change is ok, though, as long as it's consistent. If Python is going to pave the way to the future, then go for it. Don't forget that the legacy .NET and PHP code still needs to be supported until end of life. Building yourself a hodge podge of platforms and frameworks will just create more difficulty for you on the job and the company when you're no longer around.
If you feel in your heart you are acting dishonestly, then you probably are.
No one likes a dishonest person. That can't be good for your reputation.
Do your best to choose based on what is actually best, not what satisfies some underhanded motives.
It depends. I did some of what would normally just be a bash script, in Java instead at one place. Why? Because they're all Java programmers and frequently have interns/coops coming through that may or may not know anything else (and may or may not even be all that great with Java).
Other places though tend to have more experienced programmers and I expect that they'll be able to figure out another language without too much effort. So, I would go with what's "best" for the project.
I agree with what mquander says above, but you may also have to be prepared to justify why you want to use this other language to your development manager. If he/she then agrees, perhaps the language could become more widely adopted within the company.
Think of it in terms of business benefit you bring to the company, now and in the mid-term.
If you can deliver something much faster using a different technology, and it still achieves the goals, I'd go for it - but I'd still let some other people know and respect the company's final decision. If however, it's purely for yourself, then I'd probably be a litte more careful.
I think it's a really bad idea. For you, it means there's no back up in case you want to have a day (or week) off. For them, there's no one else if you leave or are taking a day off. It's a well known ploy, and, honestly, might be reason to not keep you around.
However, this could also be a chance to introduce Python into the environment. You could teach others about it, and explain to management while it's a good third language to have at the group's disposal.
I used to think that you should always pick the right language for the job at work. I'm reversing my opinion though.
The problem arises when some other guy picks a language you don't want to learn. I am concerned that I might be the guy who picks the language no one else wants to learn. Just because I think that Erlang might be the right choice for something doesn't mean that everyone else will want to learn Erlang or respect my decision for using Erlang.
"if I were to leave the company, they'd basically have nobody to maintain/add to it unless they retain on me as a consultant."
Are you saying no one else can learn Python? I find that hard to believe.
New technology is often introduced in small projects by knowledgeable people and diffused through the organization because the small projects were successful.
Use Python. Be successful. Make your case based on your successes.
I had this same problem very often. Coincidentally, it was with those two languages you mention: .NET forced on me, when I preferred to use Python (among others). Could be the opposite, I don't judge.
I refrained to use Python, because of the reasons already mentioned in other answers. I did what I thought was best for the company. Using IronPython won't make your python code any more maintainable for an unexperienced Python programmer.
However, I left the company and now I work in something more in line with my tastes. I'm much happier. In this economy you may not have this option... but it will pass. Do the right thing.
Cheers.
There is a large difference between 'prototype' or 'one-shot' code and production code. For prototyping I use whatever works fastest, but I'm very clear about its status. Production code is written in one of the approved and supported environments.
The ethics is to use the best tool for the job. If there is a tool that takes you only 20% of the time to code vs other choices, and next to no maintenance, and easy to re-factor, you have a duty to pick that tool, assuming it's extensible as you may need in the business.
If you do a good job, hiring future people and training them in terms of HOW your workplace does business should be the practice of any growing business. They will be able to learn the code if they're the right person for the business.
In your case I'm not sure if you want to use Python, unless it has native .NET support to allow your .NET world to interact with it.
Other posters have made some good points, but here's one I've not seen: Communicate the situation to management and let them decide. In other words, talk with your boss and tell him or her that there currently are more .NET developers in your area, so that if you're hit by a bus tomorrow it would easier to find someone else to maintain your code; however, there are tools you need to do your job more efficiently and they cost money (and tell them how much). Alternatively, you could do this in Python or RoR (or whatever) and use free tools, but from what you know, there aren't currently that many people in the area who know those languages. I've used "currently" a couple times here because this may change over time.
Before having this conversation, it might be good to see if you can find user groups for the alternative technology in your area, and how large they are. You could also ask on listserves if there are people who know the alternatives in your area.
Of course, the boss may tell you to keep using .NET without any tools, but in that case it's their decision to shoot themselves in the foot. (And yours to decide if you want to find a new job.)
Regarding the question as asked, I see nothing unethical about it, provided that:
It is a freely-available language. Although I am something of a FOSS partisan, that's not the point of this criterion. It needs to be freely-available (not necessarily FOSS) so that it doesn't impose costs on the company and so that others will have the opportunity to learn it if you ever need to be replaced (or if they want to compete with you for your job).
You are changing languages for solid reasons and not for the sake of creating vendor lock-in (or, if you prefer to think of it as such, "job security"). Ethics aside, you really don't want to have a job where they hate you, but are stuck with you because you're the only one who can maintain the mess you've created anyhow.
In the particular case you've described, I would suggest that switching to RoR may be the more ethical choice, as it would be decidedly unethical (not to mention illegal) to use .NET if there are required resources which are for-pay only and your employer is too cheap frugal to purchase proper licenses for them.
When in Rome... do as the Romans.
You might not be the one who as to maintain this code in the long term and not everyone wants to learn a "fringe language" to make bugfixes or enhancements.
I migrated some VBA stuff over to Perl for processing at a previous job and increased the efficiency by several orders of magnitude, but ultimately no-one else there was willing to learn Perl so I got stuck with that task longer than I wanted it.
I did that, it was Delphi in my case. I think Delphi was used often however when i was looking for a job .... i saw 3 delphi job offers in my whole life. i also saw more java/j2ee/php offers that i can remember. i think its bad idea, with the time i wasted in learning advance delphi programming i could get better with j2ee and start in better company and maybe make now more money.
If they cant find somebody to maintain the app you will always do it and when you quit they will have to re-write it. i think consultant thing is not used often.
I used to be in the "use the best tool for the job" school, but I've changed my mind. It's not enough to just ask "how can I do this job the fastest." If you think you're the only one who will ever need to look at some code, there's a good chance you're mistaken. The total cost of introducing a new language into an environment is higher than you might imagine at first.
If you just need to produce a result, not a program, then you can use whatever you want. Say you need a report or you need to munge some files. If the output is really all that matters, say it's something you could have chosen to do by hand, you can practice using any language you want.
With the release of the MVC Framework I too have been in a similar ethical delema. Use WebForms or switch over to MVC Framework for everything. The answer really is you have to do the right thing and use whatever the standard of the company is. If you deviate from the standard it creates a lot of problems for people.
Think how you would feel if you were dumped a project on VB6 when all you have been doing for years is .Net. So these are the two solutions I have come up with.
Use your fun languages for consulting contracts you do on the side. Make sure the client knows what you are doing and if they agree go for it.
Try and convince your current company to migrate over to this great new language you are working with.
If you follow these routes you will learn your language and not piss anyone off in the process.
Ruby on Rails is certainly not a fringe language. If the company is too cheap to pony up for the appropriate licensing for Microsoft's tools, then you would have no choice but to find an alternative. RoR certainly would be a reasonable choice and if helps move your career along as well, then it's win-win for both of you!
You can develop .NET adequately with free tools; cost is not a good reason to avoid that platform. Ruby on Rails is becoming reasonably mainstream for building data-driven internet websites. You haven't even told us if thats the sort of software you are building though.
There is really no way with the information that you have provided that anyone can give you a single correct answer.
If you are asking is it ethical to do your work in such a way that the company is dependent upon you, of course the answer is no. If you are asking is it ethical to develop in RoR then the answer is "we don't know" - but my opinion is that probably it would be fine if its the right tool for the job.
Don't underestimate the ability of someone else to support your work or replace you though - if you do your work reasonably well once the solution is in place any programmer worth their pay should be able to learn the platform well enough to maintain it. I've debugged, migrated and supported a few PHP applications for example without ever hardly learning the first thing about PHP. I'd be lost building a new PHP app from scratch and would never even try but its no problem to support one. I think the same would be true of the languages you mention as well - they've got the critical mass that means there is plenty of books and forums etc. Of course if its written badly enough in any language then it may be difficult to support regardless of anyone's skill in the language...
So much discussion for such a clear-cut situation...
It's not up to you, it's up to them. If they're not technical enough to make the call, as it seems, then you have to make it for them in good faith. Anything less is dishonest, and I'm fairly sure that's not in your job description ;)
You've muddied the waters with all the wandering about in the thickets of personal motivations. The answer to that one is that your personal motivations are irrelevant unless and until you've formulated the business case for the possible decisions. If you've done that and the answer still isn't clear-cut, then sure, choosing the answer you like the best is one of the nice things about being in a position to make technical decisions in the first place.
As far as the actual question goes, to my mind if the most technically apt choice is also one that very few people work with, one of two things is happening: a) It's a good choice, and the number of people working with it is going to be exploding over the next 18-24 months (e.g. Django), or b) There's something wrong with my analysis. Technologies may be on the fringe because people are slow to adopt them, but that's generally not why they stay on the fringe.
If you find yourself thinking "I can't choose technology X, that'll make it easier for them to replace me!" you're in the wrong line of work. In almost any enterprise that's not actually failing, the IT guy who makes himself easy to replace tends to move up to harder and more interesting and more lucrative work.
I would not bring a new language/framework/whatever into the place unless they understood that's what I was doing, and that if I left/was fired/was hit by a bus, they'd have to find/train someone to work with it.
I have some experience in a contractor pulling in things just because he felt like it. In some cases they were the best tool for the job (in other cases they were not), but in all cases they were not the best tool for the team that had to maintain the code. In my case the contractor was a serious jerk who didn't really give a darn about anyone else and I believe WAS trying to make himself harder to replace.
In your case, talk to your bosses. If they really don't want to spend the needed money on .NET framework tools/libs, then switching to something else may well BE the right thing to do for them, long term.
And, as someone who has spent his career walking into the middle projects that others have already started - thank you for thinking before you add a new tool to the mix.

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