TOP command is very helpful to displying current running on system status. Update and display top CPU processes periodically. We can view different types of processing status by using keys.

​du command is very simple and useful for Summarize and estimate files, directories space usage on Linux or Unix system. Can get different types of disk usage information. Also show usage of each FILE, recursively for directories.

On Unix or Linux use shell scripting If you could not calculate string, we can convert string to integer type,

You may get an error when execute shell script in linux based system, bad interpreter in Linux.

Yes, its possible to be change user home directory. By default the user working directory creating in /home, do you like to modify following below steps.

Exim is a message transfer agent (MTA) for hosts that are highly comfortable and running in Unix or Linux Operating system.