The "Sendmail" application allows Linux and Unix servers and workstations to deliver mail directly to a target mail server. Sendmail can be started from the terminal, but the application must have sufficient permissions on the system to run. You will need to change the permissions of Sendmail if you are unable to run the application. Once changed, you will be able to execute the Sendmail program, and you can then analyse it for performance or use it for its intended purpose.
Log into your Linux or Unix server or workstation as the root user.
Type "chmod a+rwx /usr/sbin/sendmail" (without quotes) to grant full permissions to the application.
Type "sendmail" on the console window. The application will now execute and you will be able to use it.
You can review the full documentation for Sendmail by typing "man sendmail" to open the manual on your server or workstation terminal.