dish

Dish (dope interactive shell) is a basic custom shell in C, providing features such as raw mode input handling, tokenizing input strings, and executing basic commands. The shell supports pipes (|) and background execution (&).

Key Components

1. Initialization and Raw Mode

   • Enables raw mode for character-by-character input processing
   • Allocates memory for input string
   • Initializes variables for input tracking

2. Main Function

   • Processes input into a single string
   • Handles program exit safely without memory leaks

3. Lexer

   • Breaks input into tokens
   • Handles spaces and special characters
   • Returns a null-terminated array of token structures

4. Execute Function

   • Creates new processes using fork()
   • Runs commands using execvp()
   • Handles parent and child processes

5. Input Processing

   • Handles Enter key for command execution
   • Manages backspace for input editing
   • Ignores arrow keys to prevent errors

6. Error Handling

   • Checks for maximum input size
   • Provides error messages for invalid inputs

7. Cleanup

   • Frees allocated memory before program exit

Features

• Raw mode input handling
• Tokenizing input strings
• Executing basic commands
• Piping support
• Background execution support

Potential Improvements

1. Enhanced keyboard functionality (e.g., arrow key navigation)
2. Implementation of a linked list for input tracking
3. Additional built-in commands
4. Command history functionality

Code Structure

The program is divided into several key functions:

• enable_raw_mode(): Sets up the terminal for raw input
• num_tokens(): Counts the number of tokens in the input
• tokenize(): Breaks the input into tokens
• execute(): Creates new processes and runs commands
• Main loop: Handles input processing and command execution

The shell provides a basic but functional command-line interface, with room for further enhancements and features.