FAQ 9.22 How do I read mail?

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intended to make it easier for perl programmers to find answers to
common questions. The core of this message represents an excerpt
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9.22: How do I read mail?

While you could use the Mail::Folder module from CPAN (part of the
MailFolder package) or the Mail::Internet module from CPAN (part of the
MailTools package), often a module is overkill. Here's a mail sorter.


my(@msgs, @sub);
my $msgno = -1;
$/ = ''; # paragraph reads
while (<>) {
if (/^From /m) {
$sub[++$msgno] = lc($1) || '';
$msgs[$msgno] .= $_;
for my $i (sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msgs)) {
print $msgs[$i];

Or more succinctly,

#!/usr/bin/perl -n00
# bysub2 - awkish sort-by-subject
BEGIN { $msgno = -1 }
$sub[++$msgno] = (/^Subject:\s*(?:Re:\s*)*(.*)/mi)[0] if /^From/m;
$msg[$msgno] .= $_;
END { print @msg[ sort { $sub[$a] cmp $sub[$b] || $a <=> $b } (0 .. $#msg) ] }


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