Re^4: Subsetting text files containing e-mails

[PeterCap]

Aha! I get it. So essentially when a paragraph is found that contains '^From:' it places a marker at the beginning of that paragraph?

I could not figure out how it was handling all the blank lines within the e-mails until I realized that it wasn't and didn't need to.

Just to be clear, in order to actually subset the file I would still need to close and reopen it, right? I'm thinking something like:

open (<MYDATA>, $filein);

while (<MYDATA>) {

    if (/^---- Email 1/ ... /---- Email2/) {

        open (<MYOUTPUT>, ">$fileout");
        print MYOUTPUT $_;
        close (MYOUTPUT);
        
    }
}

close (MYDATA);

I suppose I might create a loop so that a new value for the search terms (i.e., /^---- Email 2/ ... /^---- Email 3/ for the second iteration, etc.) is selected as well as a new output file to catch the results...

[GrandFather]

You don't need more than one pass through the source file. Just create the output files as you need them. In sketch you'd have something like:

use strict;
use warnings;

my $emailNum;
my $outFile;

$/ = '';    # Set readline to "Paragraph mode"

while (<DATA>) {
    if (!$emailNum || /^From:/im) {
        close $outFile if $outFile;

        my $fname = sprintf "mails_%06d.txt", ++$emailNum;

        open $outFile, '>', $fname or die "Can't create $fname: $!\n";
    }

    print $outFile $_;
}