I want to write a tcsh script to send email by telnetting to my mail server and engaging in a protocol transaction. I am forced to do it this was because for some reason the mail command won't ...

See how to automate sending email with the R language, a Gmail account, and the gmailr R package ...

The various tools that you can use for sending email from the command line include these, though only some of these commands lend themselves to sending email from a script.