How to check a email in linux server automatically?

I have a Ubuntu 14 server, I have to assign a email account to this server, when some person write a email to this account, the server have to open this mail automatically, and check if there are a specific information, if yes some thing happen.

I suppose that the email are stored in a data base o something like that, but I not have any idea how to start.

Any Idea

Answer

If I have correctly understood your question, what you need is a mail alias to a command.

The following may depend on the actual mail server that you use, at least it is relevant for good old sendmail, and postfix. The mail system can use an alias database (normally the file /etc/aliases) but can be hashed into a binary version. This files can contains plain aliase that simply redirect a mail address to other mail addresses, and can also contain file aliases (the mail is appended to a local file) and program aliases.

In this last case (lines are like local_address: | /path/to/program), the program is started for each mail, and it receives the message through its standard input. Read the manual for your mail server for more detailed instructions.