Email

You can use email, or electronic mail, to send and receive letters, memos, reminders, invitations, and even junk mail (unfortunately). Email can also transmit binary data, such as pictures or compiled code, as attachments. An attachment is a file that is attached to, but is not part of, a piece of email. Attachments are frequently opened by programs that are called by your mail program, so you may not be aware that they are not an integral part of an email message.

You can use email to communicate with users on your system and, if your installation is part of a network, with other users on the network. If you are connected to the Internet, you can communicate electronically with users around the world.

Email utilities differ from write in that email utilities can send a message when the recipient is not logged in. These utilities can also send the same message to more than one user at a time.

Many mail programs are available for Linux, including the original character-based mail program, Netscape/Mozilla mail, pine, mail through emacs, Kmail, evolution, and exmh, which are supplied with many Linux distributions. Another popular graphical mail program is sylpheed (sylpheed.good-day.net).

You can use two programs to make any mail program easier to use and more secure. The procmail program (www.procmail.org) creates and maintains mail servers and mailing lists; preprocesses mail by sorting it into appropriate files and directories; starts various programs depending on the characteristics of incoming mail; forwards mail; and so on. The GNU Privacy Guard (gpg or GNUpg) encrypts and decrypts email and makes it almost impossible for an unauthorized person to read.

Network addresses

If your system is part of a LAN, you can generally send mail to and receive mail from users on other systems on the LAN by using their login names. Someone sending Alex email on the Internet would need to specify his domain name (page 873) along with his login name. Use the following address to send email to the author of this book: [e-mail].