myshell 🐚

A Unix shell built from scratch in C, running on macOS.

Features

• Command execution — run any system command (ls, pwd, echo, etc.)
• cd & exit — built-in navigation and exit
• Pipes — chain commands together (ls | grep .c)
• Output redirection — save output to files (ls > output.txt)
• Colored prompt — green and blue styled prompt
• Error handling — friendly messages for unknown commands

Build & Run

git clone https://github.com/Baranidharanv06/myshell.git
cd myshell
gcc shell.c -o myshell -L/opt/homebrew/opt/readline/lib -I/opt/homebrew/opt/readline/include -lreadline
./myshell

Usage Examples

myshell> ls
myshell> pwd
myshell> echo hello world
myshell> cd ..
myshell> ls | grep .c
myshell> ls > output.txt
myshell> cat output.txt
myshell> exit

What I learned

• How a Unix shell works under the hood
• Process creation using fork() and execvp()
• Inter-process communication using pipe()
• File descriptors and I/O redirection with dup2()
• Parsing and tokenizing user input in C

Tech Stack

• Language: C
• Platform: macOS (Apple Silicon)
• Library: readline