finding and replacing lines in a file

[richee]

Hi all,

I am new to Perl but see that it offers some fantastic opportunities and am trying to use it more in problem solving but could do with a little help on a problem thats driving me nuts....
I am trying to remove certain sub headers from email, i want it to tick through the text until it reaches "content-disposition:" then delete the next two lines.

The ticking through part is no problem but i cant seem to do anything to the file once i get there.

So, in a nutshell every time it sees:
Content-Disposition: attachment; filename="attachment.pdf"; size=0;
creation-date="Thu, 12 Apr 2007 06:39:10 GMT";
modification-date="Thu, 12 Apr 2007 06:39:10 GMT"
Content-Transfer-Encoding: base64

it should change it to

Content-Disposition: attachment; filename="attachment.pdf";
Content-Transfer-Encoding: base64

the code i have is

 
use strict;
use warnings;
 
my $line_count = 0;
my $dispo_count = 0;
my $file = 'bad.MAI'; 
open(FILE, $file); #opens file 
open(PROC_FILE, ">proc_file.txt");#file to write data to check its working
 
while (<FILE>) {
 
if ( $_ =~ /^\Content-Disposition:/ ) {    
    $dispo_count ++; # this is just for information
 
      my $nextline1 = <FILE> ;
      my $nextline2 = <FILE> ;
                print PROC_FILE ("$_ $nextline1 $nextline2" ); #this is only to check the thing is finding the right place
 
               #how the hell do i delete or replace with nothihg the 2 found lines??
}
$line_count ++;
 
}
print PROC_FILE "line count = $line_count\n"; # these are just for information
print PROC_FILE "dispo count = $dispo_count\n"; # these are just for information
close(FILE);
close(PROC_FILE);
 

I was trying to use something like:
$nextline1 =~ tr/.*//;
to replace the line with nothing but i cant seem to write the the file at all.

Does anyone have any ideas what would be the best way to approach this?

Thanks a lot!

Richee.

[richee]

Hi again,

I hope nobody wasted any time time on this tomfoolery of mine. I tried a different tack and got much closer with this:

use strict;
use warnings;
 
my $line_count = 0;
my $dispo_count = 0;
my $file = 'bad.MAI'; 
open(FILE, $file); #opens file 
open(PROC_FILE, ">proc_file.txt");#file to write data to check its working
my @file = <FILE>;
 
foreach my $line (@array_of_data)
{
 if ( $line =~ /^\Content-Disposition:/ ) {
     print PROC_FILE "$line\n";
     $dispo_count ++;
     $line =~ s/Size=.*;//gi;
     print PROC_FILE "$line\n";
 }  
$line_count ++;     
} 
 
 
 
print PROC_FILE "line count = $line_count\n"; 
print PROC_FILE "dispo count = $dispo_count\n";
 
 
open DATAOUT, ">$file" or die "can't open $file $!";
 
 
foreach my $line (@file)
   {
 
   print DATAOUT "$line";
   }
 
close (DATAOUT);
 
 
close(FILE);
close(PROC_FILE);

so now i have to just replace the next 2 lines.

Cheers,

Richee

[KevinADC]

is this still what you are trying to accomplish?

So, in a nutshell every time it sees:
Content-Disposition: attachment; filename="attachment.pdf"; size=0;
creation-date="Thu, 12 Apr 2007 06:39:10 GMT";
modification-date="Thu, 12 Apr 2007 06:39:10 GMT"
Content-Transfer-Encoding: base64

it should change it to

Content-Disposition: attachment; filename="attachment.pdf";
Content-Transfer-Encoding: base64

[richee]

Hi Kevin,

Thanks for taking the time to reply, yes I am still trying to accomplish this.

I just about have it, but its so clumsy i am embarrassed to post it. I couldn't figure out how to find the search string (so Content-Disposition in this case) then delete the next two lines, then carry on searching so i had to resort to ifs for the text i wanted to delete but aside from this being rubbish it also leaves 2 blank lines in the text which doesn't really achieve what i'm trying to do.

Any suggestions?

here is what i have so far:

my $path = "C:\\Program Files\\etc";
 
 
open(FILE, $path);
 
my @array = <FILE>;
 
foreach my $line (@array)
 
 
{
 if ( $line =~ /^\Content-Disposition:/ ) {
     $line =~ s/Size=.*;//gi; 
 
 
 }  
 if ( $line =~ /creation-date=/ ) {
     $line =~ s/.*//gi;     
 } 
 
 if ( $line =~ /modification-date=/ ) {
     $line =~ s/.*//gi;     
 }   
 
 
} 
 
open DATAOUT, ">$path" or die "can't open $path $!";
 
 
foreach my $line (@array)
   {
 
   print DATAOUT "$line";
   }
close (DATAOUT);
close(FILE);
 

thanks a lot,

Richee

[richee]

Hi again,

At the risk of further embarrassment i have found some kind of way of doing what i was trying to acheive, albeit rather crudely.

open(FILE, $path);
 
my @array = <FILE>;
my $i= 0;
foreach my $line (@array)
 
{
 if ( $line =~ /^\Content-Disposition:/ ) {
     $line =~ s/Size=.*;//gi; 
     splice(@array, $i+1,2)    
 
 }  
 
 
 $i++;
 
}
 
open DATAOUT, ">$path" or die "can't open $path $!";
 
 
foreach my $line (@array)
   {
 
   print DATAOUT "$line";
   }
close (DATAOUT);
close(FILE);

I guess it could be done much better and would be interested to hear how.

Cheers,


Richee.

[KevinADC]

I will take a look later tonight when I am off work.

[KevinADC]

Assuming that you know you will always skip two lines follow Content-Disposition:

use strict;
use warnings;
my $path = 'path/to/file';
 
{
   local @ARGV = ($path);
   local $^I = '.bak'; # use inplace editing 
   while ( <> ) {
      if (/^\Content-Disposition:/ ) {
         print;
         readline <>;
         readline <>;
      }
      else {
         print;
      }
   }
}
print 'finished';

[richee]

Thanks, great stuff Kevin. Interested to see the inplace editing, practically everything i had read said it wasnt possible to manipulate files live in this way.

Regarding the readline command and the $line array variable i was using, do you happen to know if its possible to compare two elements of the array using these, so for example if $line = $line +3, or if readline = readline +3 to compare the current element with current element +3 lines. This would be really useful to know but i couldnt seem to get it to work.

Thanks again,

Richee.

[KevinADC]

Thanks, great stuff Kevin. Interested to see the inplace editing, practically everything i had read said it wasnt possible to manipulate files live in this way.

Regarding the readline command and the $line array variable i was using, do you happen to know if its possible to compare two elements of the array using these, so for example if $line = $line +3, or if readline = readline +3 to compare the current element with current element +3 lines. This would be really useful to know but i couldnt seem to get it to work.

Thanks again,

Richee.

readline does not work with arrays, only filehandles. You can compare array elements using the array index:

if ($array[n] eq $array[n+3])

where "n" is the current index number and n+3 is three elements after n.

[richee]

Fantastic, just the ticket.

Thanks,

Richee.