Ruby Forum Ruby > Create an empty file of certain size

Hi,

I need to create an empty (or at least garbage) file of a certain size.
I'm doing it the way below, but it is rather slow -- any ideas on a
quicker way?

  File.open("tmp.txt", 'w') { |f| 10.megabytes.times { f.write "a" } }

Thanks!

~ Mark

On May 15, 2008, at 4:09 PM, Mark Dodwell wrote:

>
> ~ Mark

fd.truncate( 2 ** 20 )

a @ http://codeforpeople.com/

> fd.truncate( 2 ** 20 )

Thanks that's great, didn't know about that method!

2008/5/16 Mark Dodwell <seo@mkdynamic.co.uk>:
>> fd.truncate( 2 ** 20 )
>
> Thanks that's great, didn't know about that method!

If it does not work on your platform, you can speed up your solution
by writing larger chunks:

BUFFER = ("a" * 1024).freeze
File.open("tmp.txt", 'wb') { |f| 10.kilobytes.times { f.write BUFFER } }

Kind regards

robert

Robert Klemme wrote:
> 2008/5/16 Mark Dodwell <seo@mkdynamic.co.uk>:
>>> fd.truncate( 2 ** 20 )
>>
>> Thanks that's great, didn't know about that method!
> 
> If it does not work on your platform, you can speed up your solution
> by writing larger chunks:
> 
> BUFFER = ("a" * 1024).freeze
> File.open("tmp.txt", 'wb') { |f| 10.kilobytes.times { f.write BUFFER } }
> 
Here is another way:

size = 2**30
File.open("tmp.txt","wb"){|f|f.seek(size-1);f.write("\0")}

Regards,

Park Heesob