Actually sending mail from a CentOS server/Desktop install is pretty easy. You can do that in many ways but I like this way because it is simpler. Before sending the mail, the content of your mail if you store at some place would be better. assume like I have stored my message /tmp/body file.Then I will sent my message as
mail -s "This is subject of message" firstname.lastname@example.org < /tmp/messagethats it. check for your mail in inbox/spam/junk box.