Which is why I recommend to look at Yes, even you can use CPAN and see if you really can't use a module. MIME::Lite appears to be a pure-Perl module, and thus you should be able to use it everywhere where you can put scripts by yourself.

You already have some specific answers. These are some additional observations:

1. ...wihout (sic) using external module
   and
2. ...where it's not possible to install a module for the purpose.

As a general rule (though not in this case), the phrase in 1 is justified only when the writer is interested in reinventing the wheel for educational purposes or cannot compile the module in question for the OS in use.

The clause in 2 is highly unlikely to be true (in terms of desired functionality) on any server for which the writer has the necessary permissions to install a script.

The reading suggested by moritz provides detail and in the Monastery's Tutorials section, you may find Installing Modules on a Web Server relevant, along with others in Installing Modules.

Hmmm,

In general I think you have a point, but beware of generalising too much - there are circumstances e.g. air gapped security sensitive systems, in which the propositions don't hold in a formal sense, but constraints e.g. security certification, on the installation of external, particularly public, code have the direct effect of causing them [the propositions] to appear to hold.

Been there, seen it, eaten the T-shirt ... and bloody frustrating, but educational (because you are forced to re-invent the wheel in the interests of expediency), it is.

A user level that continues to overstate my experience :-))

++ for an exception.

But note the qualifiers, "as a general" (which I understand to mean there are exceptions) and "highly unlikely" which (implicitly at least), allows for exceptions?

#!/usr/bin/perl
use strict;
use warnings;
use MIME::Base64;

my $SENDFILE = 'z.jpg';
my $FROMUSER = 'zentara';
my $FROMEMAIL = 'zentara@zentara.zentara.net';
my $TOUSER = 'zentara';
my $TOEMAIL = 'zentara@zentara.zentara.net';

open(F_MAIL,"|/usr/sbin/sendmail -t");

my $boundary = "----------90125";
print F_MAIL <<END_OF_MAIL;
Precedence: list
From: $FROMUSER <$FROMEMAIL>
To: $TOUSER <$TOEMAIL>
MIME-Version: 1.0
Subject: File attachment test
Content-Type: multipart/mixed;
    boundary=\"$boundary\"
    
This is a multi-part message in MIME format.
    
--$boundary
Content-Type: text/plain;
    charset=\"iso-8859-1\"
                    
Here is the body of the message.  A file attachment is also provided b
+elow.
        
--$boundary
Content-Type: application/octet-stream;
name=\"$SENDFILE\"
Content-Transfer-Encoding: Base64
Content-Disposition: attachment;
filename=\"$SENDFILE\"

END_OF_MAIL

#open(F_SEND,$SENDFILE) || &Error("Cannot open sendfile for MIME encod
+ing");
open(F_SEND,$SENDFILE) || die ("Cannot open sendfile for MIME encoding
+");
while (read(F_SEND,my $buf, 60 * 57 ) ) {
print F_MAIL encode_base64($buf);
}
close(F_SEND);

print F_MAIL <<END_OF_MAIL;
--$boundary--
END_OF_MAIL
close(F_MAIL);
[download]