A Unix shell written in C

Note: This project is under construction. It lacks a lot of basic functionalities that you might expect from a shell like bash or zsh.

How to use:

Note: This shell is only tested on Linux as of now. It may or may not work on MacOs. It doesn't work on Windows at all.

• Firstly, clone the repo:

git clone https://github.com/raghav-4002/unix-shell.git ~/unix-shell/
cd ~/unix-shell

• Make sure that you have GCC installed in your system.
• If you also have GNU Make installed, run the command:

make

• Otherwise, you have to manually compile it using:

gcc -Iinclude src/*.c -o shell

• You can run the shell using:

./shell

• To exit, just run exit.

Features:

• Handles all external executables, like ls, pwd, man, etc.
• Supported built-in commands:
  • cd: Change current working directory (not completed yet).
  • exit: Exits the current shell session.
  • exec: Execute an external program.
  • help: Display available built-ins (not completed yet).
• Displays the username of the current logged in user and machine name.
• Displays the current working directory.
• Can execute multiple commands separated by semicolons.

Currently working on:

• Allowing the user to edit the command before pressing enter.
• Executing semi-colon separated commands.
• Advanced logical precedence using parenthesis.
• Adding support for Pipelining.
• Adding IO redirection.
• Job control.
• Shell globbing and expansion.
• Tab auto-completion.
• Adding .rc file and history preview using arrow key and history command.
• Scripting capabilities.

How it works:

• Accepts user input in raw string format.
• Tokenizes the input using lexical analysis, separating commands from operators like && and ||, into components named elements.
• Parses these elements into an abstract syntax tree according to the precedence of logical operators.
• Traverses the tree, executing commands.