check file in use
 

Is there any ways to check which files are in use by remote users ?

E.g.
1. In Samba, who is opening which files
2. In Sendmail, who is sending files to the server
3. In Pop3, who is getting their emails
4. In MySql, who is reading a table
etc......

I mean one program or command which display all files intead of using different program to achieve this.

lsof is a command that lists open files. It might help.