LeanShell

LeanShell is a lightweight, minimalistic command-line interface (CLI) application written in C++ that provides a basic shell environment for executing built-in commands and external commands available in the system's PATH. It is inspired by Stephen Brennan's lsh (https://brennan.io/2015/01/16/write-a-shell-in-c/).

Features

• Built-in Commands

• cd: Change the current working directory.

• ls: List files and directories in the specified path.

• touch: Create new empty files.

• cp: Copy a file from source to destination.

• mv: Move a file or directory from source to destination.

• hs: Show command history.

• clrhs: Clear command history.

• exit: Exit the shell.

• help: Display a help message with command descriptions.

• echo: Print the arguments to the console.

• cat: Print the contents of files to the console.

• df: Show available disk space.

• clear: Clear the console screen.

• External Commands: Ability to run any built-in Unix commands that exist in the system's PATH.

• Command History: Maintains a history of executed commands, which can be displayed or cleared.

• Colored Output: The ls command displays directories in a different color for better visibility.

Usage

1. Clone the repository or download the source code.
2. Compile the source code using a C++ compiler. For example, with GCC:

g++ main.cpp -o leanshell

3. Run the compiled executable:

./leanshell

4. The shell prompt (>) will appear, indicating that you can enter commands.
5. Type a command and press Enter to execute it. For example:

> ls
> cd /path/to/directory
> touch file.txt
> cp file.txt file_copy.txt
> mv file_copy.txt new_file.txt
> hs
> help
> exit

6. To exit the shell, use the exit command or press Ctrl+C.

Future Improvements

• Support for redirection (>, <) and piping (|) operators.
• Handling of multiple spaces, quotes, and other special characters in input.
• Tab completion for commands and file paths- make use of the command history available.
• Display current directory path.
• Persistent command history across sessions.
• Improved error handling and error messages.
• Support for environment variables and shell scripting.