It is possible to execute commands on the remote host and to check that the output matches what is expected. This kind of check should be used with extreme caution, as it is not always portable across different flavors of Unix.
The quiet keyword tells Nessus not to show the output of the command that failed. It can be set to “YES” or “NO”. By default, it is set to “NO” and the result of the command is displayed. Similarly, the
dont_echo_cmd keyword limits the results by outputting the command results, but not the command itself.
The nosudo keyword lets the user tell Nessus not to use sudo to execute the command by setting it to “YES”. By default, it is set to “NO” and sudo is always used when configured to do so.
description: "Make sure that we are running FreeBSD 4.9 or higher"
cmd: "uname –a"
expect: "FreeBSD (4\.(9|[1-9][0-9])|[5-9]\.)"