[Linux Operating System] A shell script is a sequence of shell commands written in an executable script file. Executing this file instructs the shell to execute all commands in the order of their appearance in the script file. There are several shell scripting tutorials available on the web, e.g. search by entering the keywords Linux shell script tutorials. Go through one of these tutorials and then write a shell script that displays various system parameters by using shell commands like who, whoami, date, hostname, etc.
2. [Linux Operating System] ps is a command that displays information about all processes currently running in your system. Read man page of ps command. Enter the following commands: (1) ps -ef | more and (2) ps -aux | more. Both of these will result in displaying a long list of processes. Identify what processes are started when the system is booted, and what processes are started later on. For each process, find out who owns it, what code it is running, and how much CPU/memory it has used.
Now, store the details of all processes owned by root in a file called rootprocesses- 1, and all processes owned by you in a file called my-processes-1. Next, restart your system, and create similar files, root-processes-2 and myprocesses-
2. Compare root-processes-2 with root-processes-2, and my-processes- 1 with my-processes-1. Explain the differences between the two.
3. [Linux Operating System] free is a command that displays used and available memory in your system. Read man page of free command. Run the command free -o several times, running other programs in between, and store the results in a file. Draw a graph as follows: X-axis: MB-used; for the Y-axis, use (i) Memory Used per unit time; (ii) (Memory Used - Memory Buffered - Memory Cached) per unit time; and (3) Swap Used per unit time. Explain the behavior of this graph with respect to memory utilization in the presence of running various applications.