Use the 'ps' command. This command lists all of the processes running on the system, when they started, who the owner is, etc.
Use the 'uname -a' command. It reports on the Unix system, version, machine name, amongst other things.
Unix systems may be affected by viruses .. see related link.
See related link
The Unix operating system. The first versions of the Unix operating system were written in the "B" language, and later written in "C", which was invented in order to develop Unix on the PDP-11 machine.
Unix was developed primarily using the C language; there may be a small amount of assembler/machine code used in the boot process as well.
shell
The "who" command.
see: What_is_the_cost_of_a_Unix_server
LDAP (Lightweight Directory Access Protocol) often used in Unix and Linux environments, Active Directory is based on LDAP.
See related link.
The ls command.
ps -ef