cmail.exe -host:smtp.example.com -to:email@example.com -from:firstname.lastname@example.org "-subject:Simple test e-mail" "-body:This is just a test."Attachments
cmail.exe -host:smtp.example.com -to:email@example.com -from:firstname.lastname@example.org "-subject:The file we discussed" "-body:See attached" "-a:c:\file_path\file_name"Authentication
cmail.exe -host:Bob:email@example.com -to:firstname.lastname@example.org -from:email@example.com "-subject:Authenticated message" "-body:This message was sent using the username 'Bob' and the password 'qwerty'."Using a text file as message body
To use the content of a text file as the message body, you can pipe it in to CMail, and instruct CMail to read the message body from stdin using the -- option. As of 0.7.7, to assist with cases where CMail is being called from other programmes, you can also use -body-file.
type file.txt | cmail.exe -host:smtp.example.com -to:firstname.lastname@example.org -from:email@example.com "-subject:Body from text file" --SSL/TLS (STARTTLS)
This method is for servers supporting STARTTLS. This is the method you should use to send e-mail via GMail. In this example, the -host option is specifying port 587, which some services require you to use for message submission. You can use -requiretls instead of -starttls to only send when encryption is possible, otherwise CMail will attempt to send messages even if encryption is not offered.
From 0.8.0 onwards, STARTTLS will be used automatically if authentication is not available prior to establishing a secure connection. The -starttls setting must still be used to ensure credentials are not sent over insecure connections if authentication is offered without TLS.
cmail.exe -host:Bob:firstname.lastname@example.org:587 -starttls -to:email@example.com -from:firstname.lastname@example.org "-subject:Secure message" "-body:This message was sent securely if the server supported STARTTLS."SSL/TLS (SMTPS)
This method is for servers requiring SMTPS. You should use the method above if supported, as SMTPS is considered deprecated. This method is the equivalent to using Blat with stunnel. Note, -secureport changes the default port to 465.
cmail.exe -host:Bob:email@example.com -secureport -to:firstname.lastname@example.org -from:email@example.com "-subject:Secure message" "-body:This message was sent securely."A practical example
CMail can do a lot, but there's no such thing as a free lunch. The example below addresses the practical problem of sending a directory full of PDF files, while remaining under the default 10MB message limit imposed by many mail systems.
The script operates by constructing a supplementary configuration file for CMail (append.txt) containing a list of attachment commands, and keeping track of the total file size. When the next file would put the e-mail over the size limit, the e-mail is sent, and a new attachment list is started. There are a couple of key points to note here. Firstly, the size limit is set at 7,340,032 bytes, which is 7MB. Adding base64 encoding overhead, the resulting e-mail will safely remain under 10MB. The second consideration is that the attachments explicitly use base64 transfer encoding (-a64 setting). If CMail is asked to select the encoding to use (-a setting), any file that contains mostly text in the first 4KB would be quoted-printable encoded, which aside from being much less efficient for binary data, could put the e-mail over the maximum size.
Note, this script does not split files. Any PDF that is too large will be sent in its own e-mail, and would likely fail to send. If limits are to be exceeded, use of an archival tool such as 7-Zip is advised. This script is provided as-is. Use at your own risk.
set SRC=C:\Some Directory
if exist attach.txt del attach.txt
for /f "delims=" %%a in ('dir /b /os *.pdf') do (
set /a NEWSZ=!SZ!+%%~za
if !NEWSZ! gtr %MAXSZ% (
set /a SZ=!SZ!+%%~za
cmail.exe -host:smtp.example.com -to:firstname.lastname@example.org -from:email@example.com -config:attach.txt