💻 My Shell — Minimal Production-Level Shell

A compact, educational Unix-style shell written in C with common features useful for learning and small scripting tasks.

Highlights

• Builtins: cd, exit, history, export 🔧
• Pipelines: | support for chaining commands 🔗
• Redirection: input <, output > and append >> 🔁
• Background execution: run jobs with & ⚙️
• Variable expansion: $VAR is expanded using environment variables 💡
• Script execution: run shell scripts by passing a filename
• Signal handling: graceful Ctrl+C handling (SIGINT) 🛡️

Why this project?

• Great for learning process control, fork(), execve()/execvp(), pipes, and basic shell features.
• Minimal, contained implementation — useful as a teaching aid or starting point for enhancements.

Build

On Linux / WSL / macOS (recommended):

gcc -o myshell My_Shell.c

On Windows (use WSL, MinGW, or MSYS2):

• With MinGW (example):

gcc -o myshell.exe My_Shell.c

Notes: Some platform differences (signals, /dev/null, path behavior) may exist on native Windows — WSL provides the closest behavior to Unix.

Run

Interactive shell:

./myshell        # or myshell.exe on Windows

Run a script file:

./myshell myscript.sh

Usage Examples

• Change directory:

cd /path/to/dir

• See command history:

history

• Pipeline example:

ls -la | grep ".c" | sort

• Redirect output and append:

echo "hello" > out.txt
cat file.txt >> out.txt

• Run in background:

  sleep 10 &

• Export environment variable:

  export MYVAR=hello
  echo $MYVAR

Implementation notes (quick)

• Parsing: strtok()-based splitting on spaces; simple and intentional for clarity.
• Redirection: handled by scanning args and dup2() before execvp().
• Pipelines: splits on |, uses pipe() + multiple fork()s.
• History: in-memory history[] array (no file persistence).

Limitations & TODO

• Quoting and escaped spaces are not fully supported.
• No command-line editing (no readline support).
• No persistent history file.
• Limited error handling for malformed input.