Please write down commands to accomplish the following tasks: (40 points)

Please create a file README.txt to read/write for the owner and read for everyone else.

Please create a file Input.txt to read/write/execute for the owner and write for everyone else. You MUST use OCT format for file permission.

Please create a bash file myscript.sh that count the number of files/directories in directory /home/Ubuntu/. Turn on the files setuid bit and setgid bit without changing the current permissions.

List the contents of the directory /home/proc/ sorting by modification time and listing the most recently modified file last.

By convention, the /tmp directory is available to all users who care to create files there. What prevents one user from reading or deleting anothers temporary files? (10 points)

Explain the relationship between a files UID, a running processs real UID, and effective UID. Besides file access control, what is the purpose of a processs effective UID? (10 points)

Suppose that a user at your site has started a long-running process that is consuming a significant fraction of a machines resources. (40 points)

How would you recognize a process that is hogging resources?

Assume that the misbehaving process might be legitimate and doesnt deserve to die. Show the commands you would use to suspend the process temporarily while you investigate

Later, you discover that the process belongs to your boss and must continue running. Show the commands youd use to resume the task.

Alternatively, assume that the process needs to be killed. What signal would you send, and why? What if you needed to guarantee that the process died?