Tie::File Help

Anonymous Monk has asked for the wisdom of the Perl Monks concerning the following question:

Fellow Monks!

I respectfully ask for your help.
THe following code(below) works perfectly. The goal is to add the numeric content in the variable $count as a line to the beginning of a file.
the good code:

#!/usr/bin/perl -w
use strict;
my $count=8;
use Tie::File;
tie my @lines, 'Tie::File', 'T:\temp.txt' or die 'tie failed';
unshift @lines, "$count";
untie @lines;
[download]

Now.... I want to put the filename in a variable, $file, so that I can change the name through the variable if necessary. I now have this code:

#!/usr/bin/perl -w
use strict;
my $file="T:/temp/temp.txt";
my $count=8;
use Tie::File;
tie my @lines, 'Tie::File', "$file" or die 'tie failed';
unshift @lines, "$count";
untie @lines;
[download]

Which unfortunately doesn't work. I get the following error:

tie failed at P:\test405.pl line 9
[download]

And.... line 9 just happens to be where I am doing the file tie to the array. I did indeed verify that the file still exists and the permissions are OK. I checked in the CPAN documentation for this module, and from what I saw in it this line:

tie my @lines, 'Tie::File', "$file" or die 'tie failed';
[download]

.... should indeed work. What finite subtlety am I missing here? I am figuring that the problem must be right under my nose and I am simply missing it.
Your help and wisdom are greatly appreciated!
Thanks in advance!

Comment on Tie::File Help Select or Download Code

Replies are listed 'Best First'.
Re: Tie::File Help by deibyz (Hermit) on Apr 27, 2005 at 13:30 UTC
Try printing also `$!` to see why the tie failed. More information in perlvar	[reply] [d/l]
Re^2: Tie::File Help by Anonymous Monk on Apr 27, 2005 at 13:47 UTC
sigh ..sometimes the obvious stands before us screaming and jumping up+down... yet we do not see. Your suggestion revealed to me the exact problem. Thanks for your help!!	[reply]
Re^3: Tie::File Help by deibyz (Hermit) on Apr 27, 2005 at 13:54 UTC
It happens to me every day. That's why I always `die` with `$!` at the end of the `die` message.	[reply] [d/l] [select]
Re: Tie::File Help by polettix (Vicar) on Apr 27, 2005 at 13:11 UTC
Slashes? I see you use backslashes in the good code, and forward slashes in the bad. Flavio (perl -e 'print(scalar(reverse("\nti.xittelop\@oivalf")))') Don't fool yourself.	[reply]
Re^2: Tie::File Help by Anonymous Monk on Apr 27, 2005 at 13:22 UTC
actually It tried it this way (line4): `my $file='T:\temp\temp.txt';` [download] and this way: `my $file="T:\\temp\\temp.txt";` [download] (with the double quote the initial backslash has to be escaped lest a \t tab be interpreted) anyway.... both brought down the same error. also tried `tie my @lines, 'Tie::File', $file or die 'tie failed';` [download] ...and... `tie my @lines, 'Tie::File', "$file" or die 'tie failed';` [download] to no avail..... (same error)	[reply] [d/l] [select]
Re^3: Tie::File Help by polettix (Vicar) on Apr 27, 2005 at 13:26 UTC
Another guess: in the first working example, you use file "T:\temp.txt", while in the not-working one you use "T:\temp\temp.txt". Are you sure that directory "T:\temp" exists in drive T, and you have the rights to write it?!? Flavio (perl -e 'print(scalar(reverse("\nti.xittelop\@oivalf")))') Don't fool yourself.	[reply]
Re: Tie::File Help by bofh_of_oz (Hermit) on Apr 27, 2005 at 13:49 UTC
The funny thing is, I tried your script on a Linux box AND a Windows box, and it worked perfectly... My guess is your T: drive is a network drive... try to test the script on a local file first, just in case... -------------------------------- An idea is not responsible for the people who believe in it...	[reply]