first perl script...help anyone?

[jimcasy]

HI all,
I.m very new to Perl, but I've been told it's such a powerful language for text processing I wanted to try it and learn. So, I'm writing my first script which I need to process some text file.
Basically that's what I want to do: I have 3 files, I want to read some informations from the first 2, and then write on the third. In depth, I want to read every line from the first and retrieve that line (or part of it) in a line of the second. Now, in the second file, I want to read all the lines subsequent to the line retrieved untile a termination charachter is found (in my case, when a line equal to the dot (".") is met) and print some infos in third. I want to repeat the operation until all the lines from the first line are ended.
That's what I wrote, but it doesn't work, in particular the variable $count is always equal to 1. THat means it's not reading oll the lines from the first file.

!/usr/local/bin/perl -w

open(FILEWRITE, ">write_seg06091999.txt")|| die "Could not open $write_seg06091999.txt\n";
#open(FILESEG, "seg06091999.txt")|| die "Could not open $seg06091999.txt\n";
#open(FILEALIGN, "walign06091999.txt")|| die "Could not open $walign06091999.txt\n";
open(FILESEG, "seg_short.txt")|| die "Could not open seg_short.txt\n";
open(FILEALIGN, "align_short.txt")|| die "Could not open align-short.txt\n";
$count = 1;
my $line_align = " ";

## read every line of a file
while ($line_seg = <FILESEG>) {

while($line_align = <FILEALIGN>){
if($line_align =~ /19990609_1900_1920_inter_fm_dga.$count/){
do{

if($line_align ne "."){
$line_align = <FILEALIGN>;
print FILEWRITE $line_align, "$count\n";
}
}until $line_align eq ".";
last;
}
}
$count = $count+1;

}

you have some ideas why it's not working?
probably ny programming style and my explantion sucks, so feel free to ask for more clear explanations...

 

[travs69]

open(FILEWRITE, ">write_seg06091999.txt")|| die "Could not open $write_seg06091999.txt\n";

$write_seg0609199.txt shouldn't have the $ and you should include $!
die "Could not open write_seg06091999.txt: $!\n"; or something.

add
use strict;
use warnings;
to your script.

You should also close all your file handles after your done with them.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Travis - Those who say it cannot be done are usually interrupted by someone else doing it; Give the wrong symptoms, get the wrong solutions;

 

[MacTommy]

I would suggest you use chomp() on the lines you read, or include newlines in your patterns.

Every line has a newline at the end (that chomp will get rid of for you), so no line you read will ever equal '.' (as the line will actually consist of a dot and a newline ".\n"...).

It seems like your script will read through the entire FILEALIGN file in the first iteration of the loop. So $count is indeed always 1 on your screen. After the first iteration it will go through FILESEG till the end, incrementing $count on its way, but you'll never see this, as nothing is printed anymore.

 

[jimcasy]

actually, I solved my problem, and a great deal was the problem of the newline...I wasted quite a lot of time getting that the comparison were failing because in the original text file there was a newline after the dot...thanks for the chmop suggestion