What is true regarding the command sendmail?
A. With any MTA, the sendmail command must be run periodically by the cron daemon.
B. All MTAs, including Postfix and Exim, provide a sendmail command.
C. The sendmail command prints the MTAs queue history of which mails have been sent successfully.
D. It is only available when the sendmail MTA is installed.
題解
選項A，「sendmail」指令可以直接使用，不需要透過cron排程。
選項B，正確答案。
選項C，「sendmail」指令會從標準輸入中讀取要送出的訊息，接著存入寄信佇列中。
選項D，所有的MTA都有sendmail指令。