You can change the owner and group of a file or a directory with the chown command. Please, keep in mind you can do this only if you are the root user or the owner of the file. Set the file's owner: $ chown username somefile After giving this command, the new owner of a file called somefile will be the user username. The file's group owner will not change. Instead of a user name, you can also give the user's numeric ID here if you want. You can also set the file's group at the same time.

PCB is the Area in memory where the OS can find all the information it needs to know about a process,means PCB hold the information of all processes andkeep track of all the processes.

During lifetime of process,it go through varius states of operations which are called mode or state of process.a operating system process can be in one of following state at a time:-