Linux: Send files in e-mail from console

So I wanted to send some files, but my mailx package did not have support for the famous -a parameter.

#!/bin/bash

function create_attachment_block()
{
        echo -ne "--$BOUNDARY\r\nContent-Transfer-Encoding: base64\r\n"
        echo -ne "Content-Type: $(file -bi "$1"); name=\"$1\"\r\n"
        echo -ne "Content-Disposition: attachment; filename=\"$1\"\r\n\r\n$(base64 -w 0 "$1")\r\n\r\n"
}

if [ $# -lt 2 ]; then
        echo No files specified...
        exit 1;
fi

BOUNDARY="==combine-autogun==_$(date +%Y%m%d%H%M%S)_$$_=="
BODY=""

for a in "$@"
do
        if [ -s "$a" -a -f "$a" -a -r "$a" ]; then
                BODY="$BODY""`create_attachment_block "$a"`"
        fi
done

/usr/sbin/sendmail -oi -t << COMPLEX_MAIL
To: $1
Subject: Please see files attached
MIME-Version: 1.0
User-Agent: $0
Content-Type: multipart/mixed; boundary="$BOUNDARY"

$BODY
--${BOUNDARY}--
COMPLEX_MAIL