How to split a huge file into small pieces (per 2000 columns)?

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# 1  
Old 09-29-2011
How to split a huge file into small pieces (per 2000 columns)?

Dear all,

I have a big file:2879(rows)x400,170 (columns) like below. I 'd like to split the file into small pieces:2879(rows)x2000(columns) per file (the last small piece will be 2879x170.
So far, I only know how to create one samll piece at one time. But actually I need to repeat this work many times. I am wondering if there is a easy way I just run the code once and it will create all the samll pieces itself. Anyone can help? Thanks!!

1 0 0.898 0.123 1 0 1 0 0.7987 0.124 1 0 ...
0.123 1 0 1 0 0.7987 0.124 1 0 1 0 1 0...

Moderator's Comments:
Mod Comment
Please use code tags when posting data and code samples!

Last edited by vgersh99; 09-29-2011 at 12:57 PM.. Reason: code tags, please!
# 2  
Old 09-29-2011
What's your system? The tools I'd usually use for this may not work with such long lines on most UNIX systems.
# 3  
Old 09-29-2011
just unix system. I use cut command to create the small pieces sucessfully one by one. Just want to know if there is a easy way I can create all the small pieces at once. Thanks.
# 4  
Old 09-29-2011
"what kind of system do you want to do x with?"
"what model car do you need new brakepads for?"

I'm writing a generic solution for you... It won't be the most efficient but should work most places.
# 5  
Old 09-29-2011
sorry, I am new to unix. I don't know how to answer your questions.

Thank you for working on it.
# 6  
Old 09-29-2011
how about uname -a?

---------- Post updated at 12:30 PM ---------- Previous update was at 11:26 AM ----------

Not knowing your system means I can't use the following 5-second solutions:
  1. Shell math: 400,000 could be greater than the 65536 limit on some shells.
  2. awk: many UNIX versions of awk have a linesize limit of 2000 chars.
  3. sed: see awk.
  4. cut: how can you script the number of columns without math?
which means I'm stuck with tr and can only use awk when I set RS to space. So far it's not working too well, I always end up off by one column. I'm about to give up and try perl.

Please post your system!

---------- Post updated at 01:19 PM ---------- Previous update was at 12:30 PM ----------

One way in perl:


my $COLS=2000, %FILES, @ARR;

        @ARR=split(/[ \n]/, "$LINE");

        for($F=0, $N=0; $N<($#ARR+1); $N+=$COLS, $F++)
                $FN=sprintf("out%03d", $F);
                $FILES{$FN} || open($FILES{$FN}, ">$FN");
                print { $FILES{$FN} } join(" ", @ARR[$N..$N+$COLS-1])."\n";

$ ./ < filename

This User Gave Thanks to Corona688 For This Post:
# 7  
Old 09-30-2011
Thanks so much for your help. I will try the perl script tomorrow.

Thanks again!
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