Write the code for one of the following customized commands: 1. shell*: the environment that will execute the rest of nee command, the shell won't terminate unless the exit command gets executed. The shell displays a different command prompt (i. e. something other than $ and >). 2. tree*: this new command will create a directory and call it Diro. Then it will change the working directory to Diro, and create three empty text files namely; t1.txt, t2.txt, and t3.txt, and one empty directory, called Dir1, inside it. 3. list*: this new command will clear the terminal screen and print a detailed list of all content of the current directory (similar to ls -1) to the terminal and t1.txt. Finally, it will change the name of text file to tree. txt. 4. path*: this new command will print the path of the current directory to the terminal and t2.txt, and change the name of text file to path-info. txt. Concatenate the content of tree. txt and path. txt into t3.txt and change the last to log. txt. Finally, delete tree and path text files 5. exit*: this new command will print a list the last 4 commands to the terminal, a detailed list of all content of the current directory (similar to ls -1). Finally, it will wait for the user to hit the "return" key to terminate the shell and return the control to the original shell program on your machine.