困惑，sendmail

Console ~ $ pSs sendmail
extra/postfix 2.7.0-3
 Secure, fast, easy to administer drop in replacement for Sendmail (MTA)
community/perl-mail-sendmail 0.79-3
 Perl/CPAN Module Mail::Sendmail : Simple platform independent mailer

Console ~ $ ySs sendmail
extra/postfix 2.7.0-3
 Secure, fast, easy to administer drop in replacement for Sendmail (MTA)
community/perl-mail-sendmail 0.79-3
 Perl/CPAN Module Mail::Sendmail : Simple platform independent mailer
aur/putmail 1.4-2 (21)
 a very lightweight MTA or SMTP client that may replace the sendmail command
aur/perl-sendmail-pmilter 0.97-1 (0)
 Perl binding of Sendmail Milter protocol
aur/nullmailer 1.04-3 (8)
 a sendmail/qmail/etc replacement MTA for hosts which relay to a fixed set of smart relays.
aur/mailgraph 1.14-1 (6)
 A very simple mail statistics RRDtool frontend for Postfix and Sendmail
aur/dkim-milter 2.8.3-1 (3)
 dkim-milter consists of two parts: A milter-based application (dkim-filter) which plugs in to Sendmail to provide DomainKeys Identified Mail service, and a library (libdkim) which can be used to build DKIM-compliant applications or MTAs.
aur/geanysendmail 0.4.2-2 (11)
 GeanySendMail is a little plugin for Geany IDE to send a document (e.g. a source code file) directly from Geany as attachment of a mail by using user's mailer.
aur/sendmail 8.14.4-1 (56)
 A CLI tool for sending mail
aur/mini_sendmail 1.3.6-1 (0)
 Mini sendmail for chrooted environment.
aur/spamass-milter 0.3.1-1 (1)
 Sendmail Milter that pipes incoming mail through SpamAssassin