Dylan Turner 207004235 dpt50

Everything is working on my end to my knowledge, please let me know if you have issues! 

Test Plan:
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In testing the piping and redirection functionality of a custom shell, I considered several scenarios. Firstly, the ability to handle basic command execution without pipes or redirections. I then moved to more complex cases with output and input redirection, where commands like echo "Test" > file.txt and cat < file.txt were executed. Piping between commands,  like echo "Hello" | tr 'a-z' 'A-Z', was important for testing the ability to transfer output from one command as input to another. To address more intricate usage, i tested combinations of pipes and redirections. For example: echo "Sample Text" > out.txt | cat < out.txt.

Error handling was also important, I tested responses to invalid syntax and commands. Finally, I included tests with built-in commands combined with pipes and redirections. 

Each test was performed by directly inputting commands into the shell and comparing the outcomes with those from the standard shell.


Test for Batch Mode:
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1. './mysh myscript.sh'
   -> Setup: Create a file myscript.sh and add whatever commands you want/
   -> Expected Result: Each command will be executed.


Test for Redirections:
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1. 'echo "Hello World" > output.txt'
   -> Expected Result: A file named output.txt is created with the content "Hello World"


2. 'cat < input.txt'
   -> Setup: Create a file called input.txt and add some content to it.
   -> Expected Result: The content of input.txt is displayed on the screen.

3. 'echo "New Line" > replace.txt'
   -> Setup: Create a file replace.txt.
   -> Expected Result: The "New Line" should be replace the content in replace.txt.

4. 'cat < input.txt > output.txt'
   -> Setup: Create a file input.txt with content.
   -> Expected Result: The content of input.txt is copied to output.txt.

5. 'nonexistentcommand > output.txt'
   -> Expected Result: An error message indicating the command is not found, and output.txt should be created but empty.

6. 'cat < empty.txt'
   -> Setup:  Create an empty file empty.txt.
   -> Expected Result: No output (as the file is empty).

7. 'cat < nonexisting.txt'
   -> Expected Result: An error message indicating the file doesn’t exist.

8. 'cat < input1.txt > output1.txt'
   'cat < input2.txt > output2.txt'
   -> Setup: Create input1.txt and input2.txt with different contents
   -> Expected Result: output1.txt contains the content of input1.txt, and output2.txt contains the content of input2.txt.

9. 'echo "Test" >'
   -> Expected Result: An error message indicating invalid command syntax.

10. '<' or '>'
   -> Expected Result: It should give an error saying you didn't provide a valid address to redirect.
   
Test for Pipelining:
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1. 'echo "Test" | tee output.txt'
   -> Expected Result: "Test" should be printed to the terminal as well as added to output.txt file.

2. 'echo "Hello, World!" | cat'
   -> Expected Result: "Hello World" is printed to the console.

3. 'echo "Sample Text" > temp.txt | cat < temp.txt'
   -> Expected Result: "Sample Text" should be printed to the console.

4. 'ls *.txt | grep [pattern]'
   -> Expected Result: All the files matching the pattern should be listed.

5. 'cat non_existing_file | sort'
   -> Expected Result: Should output error for non existing file.

6. 'echo "Sample Text" | tr 'a' 'b''
   -> Expected Result: This should change all 'a's to 'b's in the output.

7. '|'
   -> Expected Result: It should give the error: "Syntax error: empty command before pipe"