Splitting a Mail header using Perl

From wew@bearnet.com Fri Jun 27 20:31:48 1997
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 27 Jun 1997 20:31:47 -0000
Date: Fri, 27 Jun 1997 13:31:42 -0700 (PDT)
From: wew@bearnet.com
To: You There <you@overthere.com>
Message-Id:
 <199706272031.NAA08953@luna.bearnet.com>
Subject: Welcome to the world of email!

while(<>) {
 chomp;
 last unless $_; 
 next unless /^\w*:/; 
 ($lhs, $rhs) = split /:\s*/;          
 $headers{uc $lhs}  = $rhs;
}

1. The line last unless $_; ends the loop at the first blank line.
   The last statement tells a looping structure to go to the last possible increment of the loop, complete the cycle, then exit. We will be looking at last in more detail in Module 5.
2. The line next unless /^\w*:/; skips old Unix-style headers that do not have a colon.
   The next statement tells a looping structure to skip the remaining steps in a given cycle of the loop and go to the next increment.
   We will be looking at next in more detail in Module 5.
3. The %headers hash will get the mail headers (except duplicate header lines).

print "on $headers{DATE},
   $headers{FROM} said: . . . \n";

 
#!/usr/bin/perl -w

my ($lhsogin, $passwd, $uid, $gid,
  $gcos, $home, $shell);
open(PASSWD, '</etc/passwd');
while (<PASSWD>) {
 chomp;
 ($lhsogin, $passwd, $uid, $gid, $gcos,
     $home, $shell) = split /:/;
 print "$lhsogin ($gcos): UID: $uid,
     HOME: $home, SHELL: $shell\n";
}