The sendmail command is a generic interface to various mail transfer agents (MTAs), such as

Sendmail, Postfix, Exim, Qmail, etc. The sendmail command is used to send emails from the

command line or from other programs that need to deliver emails. The sendmail command accepts

various flags and parameters to specify the sender, recipient, subject, body, and attachments of the

email. The sendmail command also reads the standard input for the email content if no file is

specified. The sendmail command is part of the sendmail package, which is the original and most

widely used MTA for Unix-like systems. However, other MTAs, such as Postfix and Exim, also provide

a sendmail command for compatibility reasons. The sendmail command provided by these MTAs

may have slightly different syntax and options, but they all support the basic functionality of sending

emails. Therefore, the statement that all MTAs, including Postfix and Exim, provide a sendmail

command is true123.

The other statements are false. The sendmail command does not need to be run periodically by the

cron daemon, as it is not a daemon itself, but a command-line tool. The sendmail command does not

print the MTA’s queue history, but rather sends the email to the MTA for delivery. The sendmail

command is not only available when the sendmail MTA is installed, but also when other MTAs that

provide a sendmail command are installed. Reference: 1: Linux Sendmail Command Help and

Examples - Computer Hope 2: Send Email in Linux from Command Line | DigitalOcean 3: 5 Ways To

Send Email from Linux Command Line - TecAdmin