UNIX for Advanced & Expert Users

Hi! Perderabo,

Excellant Analysis..

Perderabo,

How do you get 746 files for the 2 character names? 254 *2 is 508...



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one other way that is a simple loop...

cd /dir/to/check/

for name in `ls *`
do
grep "where john is going" $name
done > file.out 2>err.out

This will capture the output in a file and any errors.

The thread that would not die...

First, your "ls *" is going to have the same problem. There too many filenames to build the list all at once.

As for how I did the math. We want to build a list of 1000 filenames and we want the list to be as short as possible. We start by using as many 1 character filenames as possible. There are 256 possible values for a byte. But you can't use null for a filename. Nor can you use /. So that gives us 254 possible 1 character filenames. But we want 1000 filenames. 1000 - 254 = 746. We still need 746 more filenames. We will make those 2 characters long because we want the list as short as possible. At this point, we have (254 + (2 * 746)) = 1746 characters in our list of filenames. But we can't run the names together. We need a space between the names and that takes 999 spaces. So 1746 + 999 = 2748 is the shortest possible list of 1000 files.

Now here is a confession... my logic that jyotipg praised has a flaw. And the correct answer is actually 2751. But I won't tell why. I know that you'll enjoy finding my flaw on your own.

ROFL

I just realized 1000 - 254 =756 hehe... sorry long day... basic math here...

Yes I realized that the ls * was the same mistake... after i posted it. That works better on directories where there are not normally 1000 files in the dir...


also, 1746 + 999 = 2745, not 2748 You had that right in your previous post... +2 bytes for the command "l " gives you 2747... which was your first answer as well...

not sure I can see the flaw, Im kinda out of it today...

original post by kelas_magnum
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also, 1746 + 999 = 2745, not 2748 You had that right in your previous post... +2 bytes for the command "l " gives you 2747... which was your first answer as well...
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magnum,
you missed out adding 1 byte for the space between "ls" and "*". That makes it 2747 + 1 = 2748 as originally said by perderabo.

But I cant understand the mystery behind the magic number of "2751"..