Re: how to give size to a file at the time of creation

Not sure why you would want to start off with a big file but here you go, This makes a big file full of zeros. You could also use pack to get a null and fill it with those if you prefer. Or question marks as the requirement is puzzling :)

use strict; use warnings;

my $file = "test.meg";
my $mb   = 1024 * 1024;
my $meg  = '0' x $mb;

open my $fh, '>', $file or die "yuck, $file: $!\n";
print $fh $meg;
seek  $fh, 0, 0;  # rewind to print at start. I guess you want this
print $fh "I Write\n";
close $fh;
[download]

Cheers,
R.

Pereant, qui ante nos nostra dixerunt!

Comment on Re: how to give size to a file at the time of creation Download Code

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Re^2: how to give size to a file at the time of creation by Tux (Canon) on May 03, 2013 at 08:00 UTC
If your filesystem supports sparse files, you don't need to write it all, one byte will do: `$ rm -f xx ; perl -wE'open$a,">","xx";seek$a,1048575,0;print$a "x"' ; +ls -l xx -rw-rw-rw- 1 merijn users 1048576 May 3 09:59 xx` [download] Enjoy, Have FUN! H.Merijn	[reply] [d/l]
Re^3: how to give size to a file at the time of creation by Random_Walk (Prior) on May 03, 2013 at 08:59 UTC
I tried `seek` first, but I am on a work XP box and it just gave me a small file. Like you said if your OS supports... Cheers, R. Pereant, qui ante nos nostra dixerunt!	[reply] [d/l] [select]