OS Ex5: Events Management
Nicole Sadagurski

An events management system. The system is composed of one server and multiple clients. 
After a client registers to the service, it can ask to receive details about new events created by 
other registered clients, RSVP for an event, asks to get all clients that RSVP’ed for specific 
event and more. This is a simple communication protocol between the server and the
client. This protocol should define how the server can know which command to execute (register, create a
new event, etc.), which client sends the command, etc.

The command line for running the server is: emServer portNum
For example: emServer 8875.

The command line for running the client is: emClient clientName serverAddress serverPort
For example: emClient Naama 127.0.0.1 8875.

Upon execution the client will wait for commands from stdin (keyboard). The client will support all the
commands specified below. A command is defined to be one line, i.e. all the text typed until an ENTER
key is pressed is considered a single command.
In addition, the client should also maintain a log. For more details see ‘Client Log’ section below.
In case that the client fails to connect the server, print the error to log (see ‘Error Handling’) and exit(1).

The server should maintain a log file named emServer.log, which includes all the commands it received.