mail 預設使用 sendmail 命令發送郵件
cat /etc/fstab | mail -s "Hello" netkiller@msn.com
通過SMTP發送郵件，創建 /etc/mail.rc 配置檔案
vim /etc/mail.rc
--- 增加如下內容 ---
set from=yourname@your-domain.com
set smtp=mail.your-domain.com
set smtp-auth-user=yourname
set smtp-auth-password=yourpasswd
set smtp-auth=login