I looked at the archives and found a mail by NYMI Jose where the code was pretty neat. It was actually for inserting in the middle of the file. However, I could not get it to append on top. I am enclosing the mail containing his code as attachment if someone likes to comment.
Jenda, I like the approach proposed by you. But I've the same question Ajey asked (Why 8*1024)?
Rajesh
-----Original Message-----
From: Jenda Krynicky [mailto:[EMAIL PROTECTED]]
Sent: Friday, October 29, 2004 7:29 AM
To: [EMAIL PROTECTED]
Subject: RE: Append on top
From: [EMAIL PROTECTED]
> This is the way I would do it, however my code has been subject to
> criticism more that once in the past :)
>
> open (FILE, "<myfile.dat") or die;
> @file = <FILE>;
> close (FILE);
> $new_data = "This is my new line that I am going to put at the top\n";
> unshift (@file, $new_data); open (FILE, ">myfile.dat") or die; print
> FILE @file; close (FILE);
:-)
This is definitely a workable solution, there are just a few things
to keep in mind.
1)This would mean that the whole file is read into the memory.
2)This would force Perl to search for end-of-lines and create an
array.
3) You open the file in text mode in both cases. This may change the
type of newlines in the file!
So it's fine for small files, but not so great for bigger ones.
If you want something more efficient you might try something like
this:
open NEWFILE, '>', 'myfile.dat.tmp'
or die "Can't create myfile.dat.tmp: $^E\n";
print NEWFILE "the new stuff to put on top\n";
...
open OLDFILE, '<', 'myfile.dat'
or die "Can't open the original file myfile.dat: $^E\n";
binmode(OLDFILE);
binmode(NEWFILE);
my $buff;
print NEWFILE $buff
while (read OLDFILE, $buff, 8*1024);
close NEWFILE;
close OLDFILE;
rename 'myfile.dat.tmp' => 'myfile.dat';
Jenda
===== [EMAIL PROTECTED] === http://Jenda.Krynicky.cz =====
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From: NYIMI Jose (BMB) [EMAIL PROTECTED] Sent: Thursday, May 06, 2004 12:44 AM To: [EMAIL PROTECTED] Subject: RE: How do I append text to a text file - in the 3rd row ?
Does this helps ?
#!perl -w
use strict;
my $text="this is appended text";
while(<DATA>){
print;
print "$text\n" if $. == 3;
}
__DATA__
line1
line2
line3
line4
Line5
OUTPUT:
line1
line2
line3
this is appended text
line4
Line5
José.
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