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Tree exercise

Problem statement

Write a command line program that implements Unix tree like functionality. Read the man page for grep if you don't know what it does. Implement all options such as -f (print relative filepath), -d (print only directories), -L (print only specified levels of the tree), -p (print file permissions), -t (sort files by last modification time), -X (print output in XML format), -J (print output in JSON format).

The program should have the following features.

Story 1

Print tree structure recursively with proper formatting for a given directory. Also, print a summary at the end.

➜  student-grading-java git:(main) tree src
src
├── main
│   ├── java
│   │   └── in
│   │       └── one2n
│   │           └── exercise
│   │               ├── Grade.java
│   │               ├── Grader.java
│   │               └── Student.java
│   └── resources
└── test
    ├── java
    │   └── in
    │       └── one2n
    │           └── exercise
    │               └── GraderTest.java
    └── resources
        └── grades.csv

12 directories, 5 files

Assumptions:

Your program behaviour should be the same as thetree command.

The output is printed on STDOUT.

Use pipe (|) and dashes (--) to indent vertically and horizontally.

The tree utility is packaged as a standalone binary (./tree). Based on the programming language you're using, you may be able to create a standalone utility (e.g., in Go). If not, use any CLI execution method in your language (e.g. java -jar tree.jar for Java)

Expectations:

Write test cases for empty directories, nested empty directories, directories with multiple files, etc.

Your code should handle errors when there is no directory read (or execute) permission for nested directories.

Story 2 (listing option)

Print the relative path to the directory being searched.

➜  student-grading-java git:(main) tree -f src
src
├── src/main
│   ├── src/main/java
│   │   └── src/main/java/in
│   │       └── src/main/java/in/one2n
│   │           └── src/main/java/in/one2n/exercise
│   │               ├── src/main/java/in/one2n/exercise/Grade.java
│   │               ├── src/main/java/in/one2n/exercise/Grader.java
│   │               └── src/main/java/in/one2n/exercise/Student.java
│   └── src/main/resources
└── src/test
    ├── src/test/java
    │   └── src/test/java/in
    │       └── src/test/java/in/one2n
    │           └── src/test/java/in/one2n/exercise
    │               └── src/test/java/in/one2n/exercise/GraderTest.java
    └── src/test/resources
        └── src/test/resources/grades.csv

12 directories, 5 files

Expectations:

Handle argument parsing in the code

Unit tests

Can you reuse the code and design from the previous story? How will you refactor your existing code to make this code reuse possible?

Story 3 (listing option)

Only print directories, not files.

➜  student-grading-java git:(main) tree -d src
src
├── main
│   ├── java
│   │   └── in
│   │       └── one2n
│   │           └── exercise
│   └── resources
└── test
    ├── java
    │   └── in
    │       └── one2n
    │           └── exercise
    └── resources

12 directories

Expectations:

Reuse code from previous stories as much as possible. Make your code modular and extensible.

Write test cases for this story.

Story 4 (listing option)

Allow traversing specified nested levels only.

➜  student-grading-java git:(main) tree -L 3 src
src
├── main
│   ├── java
│   │   └── in
│   └── resources
└── test
    ├── java
    │   └── in
    └── resources
        └── grades.csv

8 directories, 1 file

Expectations:

As mentioned in previous stories, reuse code as much as possible.

Unit tests

Story 5 (file option)

Print file permissions for all files.

➜  student-grading-java git:(main) tree -p src
src
├── [drwxr-xr-x]  main
│   ├── [drwxr-xr-x]  java
│   │   └── [drwxr-xr-x]  in
│   │       └── [drwxr-xr-x]  one2n
│   │           └── [drwxr-xr-x]  exercise
│   │               ├── [-rw-r--r--]  Grade.java
│   │               ├── [-rw-r--r--]  Grader.java
│   │               └── [-rw-r--r--]  Student.java
│   └── [drwxr-xr-x]  resources
└── [drwxr-xr-x]  test
    ├── [drwxr-xr-x]  java
    │   └── [drwxr-xr-x]  in
    │       └── [drwxr-xr-x]  one2n
    │           └── [drwxr-xr-x]  exercise
    │               └── [-rw-r--r--]  GraderTest.java
    └── [drwxr-xr-x]  resources
        └── [-rw-r--r--]  grades.csv

12 directories, 5 files

Story 6 (sorting option)

Sort the output by the last modification time instead of alphabetically (the default). Note the actual output is just for indication only.

➜  student-grading-java git:(main) ✗ tree -t src
src
├── main
│   ├── java
│   │   └── in
│   │       └── one2n
│   │           └── exercise
│   │               ├── Grade.java
│   │               ├── Grader.java
│   │               └── Student.java
│   └── resources
└── test
    ├── java
    │   └── in
    │       └── one2n
    │           └── exercise
    │               └── GraderTest.java
    └── resources
        └── grades.csv

12 directories, 5 files

Story 7 (XML/JSON option)

Print output in the xml format.

X Turn on XML output. Outputs the directory tree as an XML formatted file.

J Turn on JSON output. Outputs the directory tree as a JSON formatted array.

➜  student-grading-java git:(main) ✗ tree -X -L 4 src
<?xml version="1.0" encoding="UTF-8"?>
<tree>
  <directory name="src">
    <directory name="main">
      <directory name="java">
        <directory name="in">
          <directory name="one2n">
          </directory>
        </directory>
      </directory>
      <directory name="resources">
      </directory>
    </directory>
    <directory name="test">
      <directory name="java">
        <directory name="in">
          <directory name="one2n">
          </directory>
        </directory>
      </directory>
      <directory name="resources">
        <file name="grades.csv"></file>
      </directory>
    </directory>
  </directory>
  <report>
    <directories>10</directories>
    <files>1</files>
  </report>
</tree

Story 8 (graphics option)

Do not print the indentation lines, typically used in conjunction with the -f option. Also, remove as much whitespace as possible when used with the -J or -x options.

➜  student-grading-java git:(main) ✗ tree -if src
src
src/main
src/main/java
src/main/java/in
src/main/java/in/one2n
src/main/java/in/one2n/exercise
src/main/java/in/one2n/exercise/Grade.java
src/main/java/in/one2n/exercise/Grader.java
src/main/java/in/one2n/exercise/Student.java
src/main/resources
src/test
src/test/java
src/test/java/in
src/test/java/in/one2n
src/test/java/in/one2n/exercise
src/test/java/in/one2n/exercise/GraderTest.java
src/test/resources
src/test/resources/grades.csv

12 directories, 5 files

Feel free to make suitable assumptions if needed, and ensure to document them in README.md

🌲Tree in GO