IN JAVA Write a program to process some basic commands for file and directory manipulation in

operating systems. Operating systems typically allow a user to organize files in a hierarchical $($tree

structure$)$ fashion. This provides better organization and makes it easy to locate a file. The commands

are as follows:

$$ init

This command appears at the beginning of the input to indicate initialization $($starting an empty file

system$).$ An empty file system contains only the 'root' directory, which is always designated as $\text{'}/$home$\text{'}.$

This will also become the current directory. The init command is used later in the input when one wants

to start with an empty file system again $($all files and directories are deleted$).$

$$ end

This command indicates the end of input $($program terminates$).$

$$ mkfile filename

COSC $2436$ S$24$

$5$

This command creates a file in the current directory. The filename will be in the range $[1,10]$ characters

long and consists of only letters $($upper and lower case$)$ and digits.

$$ mkdir dirname

This command creates a directory $($subdirectory$)$ in the current directory. The dirname will be in the range

$[1,10]$ characters long and consists of only letters $($upper case and lower case$)$ and digits. The mkdir

command will not be used to create more than five levels of subdirectories in the file system hierarchy

$($the file system hierarchy will have at most five levels not including the root directory$).$

$$ cd path

This command is used to change to a different directory. The path can be $\text{'}..\text{'}$ which indicates go up to

the parent directory, a dirname which goes down to the specified subdirectory, or any combination of

$\text{'}..\text{'}$ and dirnames, separated by $\text{'}/\text{'},$ to go up and$/$or down the tree multiple times in one command.

There will be at most five $\text{'}/\text{'}$ in path, and the result will always be a valid directory.

$$ ls

This command is used to list the file$/$directory names in the current directory. List the names in increasing

order. Assume that there will be at most $20$ distinct names $($at most $20$ file$/$directory names in any

directory$),$ and no more than $5000$ user$-$created names in the entire file system. If the current directory is

empty $($contains no files or directories$),$ print a message indicating so$.$

Input will be from a data file where an input command starts in column one. If an input line

consists of two parts, there will be exactly one space separating the two parts. Only the commands init

and ls produce output to the screen. The init command generates only a heading. The ls command

generates a heading and the information requested. Note, for ls$,$ the heading includes the current

directory. At the top level, this will be $/$home$.$ At the lower levels, it includes the rest of the path as well.

Assume that every file system will have one or more ls commands $($there will be one or more ls after

each init$).$ The file is terminated with the end command.

Output to the screen the appropriate file system listings formatted according to the sample shown

below. Let the user input the file name from the keyboard. Finally, the program should ask if the user

wants to run the program again $($Check case$).$ Use a tree data structure. Refer to the sample output

below.