adding attachment using sendmail from unix

Sendmail is an extremely simplistic program. It knows how to send a blob of text over smtp. If you want to have attachments, you're going to have to do the work of converting them into a blob of text and using (in your example) p.write() to add them into the message.

That's hard - but you can use the email module (part of python core) to do a lot of the work for you.

Even better, you can use smtplib (also part of core) to handle sending the mail.

Check out http://docs.python.org/2/library/email-examples.html#email-examples for a worked example showing how to send a mail with attachments using email and smtplib

Use the email.mime package to create your mail instead of trying to generate it manually, it will save you a lot of trouble.

For example, sending a text message with an attachment could be as simple as:

from email.mime.multipart import MIMEMultipartfrom email.mime.text import MIMETextfrom email.mime.application import MIMEApplicationmsg = MIMEMultipart()msg['From'] = 'fromaddress'msg['To'] = 'toaddres'msg['Subject'] = 'subject'msg.attach(MIMEText('your text message'))with open(filename, 'rb') as f:    attachment = MIMEApplication(f.read(), 'subtype')    attachment['Content-Disposition'] = 'attachment; filename="%s";' % filename    msg.attach(attachment)message = msg.as_string()

Then you can write the message to sendmail, or use smtplib to send it.

'subtype' should either be replaced with the mime subtype of the attached document, or left out to send the attachment with the default type of application/octet-stream. Or if you know your file is text, you can use MIMEText instead of MIMEApplication.

I normally use the following to send a file "file_name.dat" as attachment:

uuencode file_name.dat file_name.dat | mail -s "Subject line" arnab.bhagabati@gmail.com