Shell in C++

Overview

This is a simple shell written in C++ from scratch. It supports various shell-like features including command execution, piping, background processes, and I/O redirection.

Features

• Execute Commands: Run standard system commands.
• Change Directory (cd): Navigate between directories.
• Help Command (help): Display available commands.
• Background Execution (&): Run processes in the background.
• Check Background Processes (checkbg): View running background jobs.
• Piping (|): Connect commands using pipes.
• I/O Redirection (> and >>): Redirect command output to files.

Installation & Compilation

Prerequisites

• C++ Compiler (G++ recommended)
• Make (for compilation automation)

Build Instructions

To compile the shell, use the provided Makefile:

make

This generates the executable shell.

Running the Shell

After compilation, run the shell with:

./shell

Cleaning Up

To remove compiled files, run:

make clean

Usage

Running Commands

You can run any system command just like in a normal shell:

ls
pwd
echo "Hello, World!"

Changing Directories

cd <directory>

Example:

cd /home/user

Background Execution

Run a command in the background by appending &:

top &

Use checkbg to view background processes:

checkbg

Piping Commands

Use | to pass the output of one command as input to another:

ls | grep .cpp

I/O Redirection

• Overwrite file output:

  echo "Hello" > file.txt

• Append to a file:

  echo "Hello Again" >> file.txt

Display Help

Run:

help