Interactive POSIX Shell

This repository contains the implementation of an interactive POSIX-compatible shell. The project showcases process management, input parsing, and system-level functionality with various built-in commands and features.

Features

• Command Execution: Executes both built-in and external commands.
• Piping and Redirection: Supports pipes (|) and I/O redirection (<, >).
• Job Control: Handles foreground and background processes (&).
• History Management: Maintains a command history (up to 20 commands) across sessions.
• Signal Handling: Processes interrupts like Ctrl+C, Ctrl+Z, and Ctrl+D.

File Descriptions

• headers.h: Contains all include files, function definitions, and extern variables.
• main.cpp: Driver code that decides which methods to call.
• prompt.cpp: Displays the shell prompt.
• parse_input.cpp: Parses and tokenizes the user input.
• cmd_handler.cpp: Decides which command to call based on parsed input.
• background.cpp: Forks and runs processes in the background.
• cd.cpp: Implements the cd command for changing directories.
• ls.cpp: Implements the ls command to list directory contents.
• pinfo.cpp: Displays process information.
• pipe.cpp: Manages and executes commands with pipes.
• pwd.cpp: Implements the pwd command to display the current working directory.
• redirection.cpp: Handles input and output redirection.
• search.cpp: Recursively searches for a file in the current directory.
• sig_handler.cpp: Manages signals like Ctrl+Z, Ctrl+C, and Ctrl+D.
• makefile: Configuration file to compile all .cpp files.
• history.cpp: Implements the history command, storing up to 20 commands across sessions in a file.

Execution

Run the following commands in a terminal (Linux) to compile and execute the shell:

make
./a.out

Assumptions

• Pipes (|) and I/O redirection operators (<, >) are preceded and succeeded by spaces.
• The user runs the executable (a.out) from the directory where it is located.

Examples

Running Commands

> ls -la
> echo "Welcome to the interactive shell"

Background Processes

> sleep 10 &

Piping and Redirection

> cat file.txt | grep "keyword"
> ls > output.txt

History Command

> history

Searching Files

> search myfile.txt

Project Structure

.
├── src/                # Source code files
├── include/            # Header files
├── makefile            # Build system configuration
└── README.md           # Documentation

Contributing

Contributions are welcome! Feel free to open an issue or submit a pull request.