Command line tools tutorial (1) cocoanetics usd to myr exchange rate

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Honestly I was very much excited when I found that I can use my current knowledge of Objective-C and Foundation classes like NSString to also build nifty little tools us market futures cnbc. Previously I had to resort to bash script to perform one-off operations on files that where too tedious to do manually convert rmb to usd. But knowing what I am going to show you in this article will enable you to also write these littler helpers.

I believe that beginners should rather start with writing a couple of command line tools before diving into building user interface driven apps pound dollar exchange rate live. Commend line tools are linear and thus their function is easier to grasp nis to usd. They are more akin to “functional programming” then “object oriented programming” if you will.

You see how I changed into the Debug output directory and executed the program there passing one extra parameter.


The dot slash is necessary to tell the shell that it should take the stringsextract binary right there in the current directory mxn to usd. Otherwise it would go off searching the set up system paths usd brl chart. You also see that argv[0] does not actually contain the absolute path, but always how it was called.

Now this works, but it might be a bit tedious to work with while we are still testing and debugging our tool ashley furniture warehouse edison nj. Fortunately Xcode allows us to specify command line arguments in the schema gender identity. If one argument contains whitespace you need to put it in quotes.

As a final step in this chapter let us add a usage text which is to be output if somebody calls this program of ours without the required one parameter.

Great post, thanks, and great idea binary code translator to text. All in all we’re all used with scripting language and we never try to consider Obj-C command line utilities. Typically my rule of thumb is that as soon as I need to repeat a process more than 5 times in a row then this operation it is worth a script that automatizes it. Typically I use perl instead of basic Unix scripting tools such as shell scripting, awk, sed or just piping them (apart a few cases). Infact the small overhead needed by perl to do basic stuff is well compensated by the power of the language.

But the issue with all scripting languages is that they don’t come with a corresponding GUI so when you want to embed a script in a GUI you must rely on Automator or use some terrible stuff like Tk…

Now I think that the extra effort of writing Obj-C command line tools is well compensated by the power of the Cocoa framework, which gives you high level to some system features – just consider file system access but even GCD if the task is complicated – but at the same time as soon as you’re happy with your command line tool it is easy to add the native OSX GUI on the existing Obj-C code just giving you the possibility to have a powerful command line tool + a native GUI (with access to a subset of the command line functionalities).

An example of this was my recent need to customize a set of pictures to be added to an iOS app euro pound conversion rate. These pictures had different sizes and aspect ratios so managing them and fitting for the iOS app required several resize and crop tasks, not easy to manage with Automator only. So I wrote a command line tool (which required as input the source directory and a few resizing parameters) to speed up the whole job. Later I found that adding a GUI that allowed me to interact with the process (pick photo, show on screen, show resized/cropped version, accept/reject) was easy by re-using the existing source code. So using native Obj-C instead of perl or python was a great choice (and all in all the overhead is limited to running Xcode instead of vim…)


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