For loop and read from different directories Post: 303001156

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Top Forums Shell Programming and Scripting For loop and read from different directories Post 303001156 by rovf on Friday 28th of July 2017 02:37:33 AM

07-28-2017

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Let's line out the basic idea:

I would first read the content of each directory into a separate array, in this case 3 arrays (A, B, C). Then I would set up an associative array (let's call it SEEN), where I enter the basename from each file which has already been processed. Checking SEEN before processing a file allows me to skip the files which have already been processed. I then would have a single loop, ranging over the indexes of the longest array. Inside the loop, I would use the loop index to access the arrays A, B and C.

One design decision is, whether the number of directories is always constant (3) or can be variable too. If there is no inherent necessity, why it must be 3 directories, and not 2 or 4, I would make this variable too.

Now it comes for choosing the programming language. You need a language which supports arrays and associative arrays. For shell scripting, it means that you can use Zsh or bash or - I think - ksh.

If you decided to make the number of directories a variable too, you **can** do it in shell scripts, but I find it a bit invonvenient. For this type of task, I would consider a more general programming language, such as Ruby or Perl.

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