Suppose you want to know what processes get launched at a given time on your Linux box like Ubuntu, you can use Auditd. Run the following commands.
apt-get install auditd auditctl -a task,always ausearch -i -sc execve
Sources
logging – How can I log all process launches in Linux – Super User. http://superuser.com/questions/222912/how-can-i-log-all-process-launches-in-linux