POSIX-like Shell in Go

A lightweight command-line shell implementation written in Go.

Features

• REPL Loop: Interactive prompt ($ ) with standard input parsing and line trimming.
• Builtin Commands:
  • exit: Gracefully exits the shell.
  • echo: Prints arguments back to standard output.
  • type: Checks whether a given command is a shell builtin or resolves its full binary path using $PATH.
  • pwd: Prints the current working directory.
  • cd: Changes the current working directory.
• External Command Execution: Locates and executes external binaries found in $PATH using os/exec, streaming stdout and stderr back to the terminal.
• PATH Resolution: Manual PATH inspection to inspect executable permissions (0111) across directory splits.

Getting Started

Prerequisites

• Go 1.20 or later installed on your system.

Running locally

1. Clone the repository:

   git clone https://github.com/jim3/go-posix-shell.git
   cd go-posix-shell

2. Run the shell directly:

go run main.go

3. Or compile and execute the binary:

go build -o go-posix-shell main.go
./go-posix-shell

Usage Example

$ ./go-posix-shell
$ echo Hello, World!
Hello, World!
$ type echo
echo is a shell builtin
$ type ls
ls is /usr/bin/ls
$ type nonexistent
nonexistent: not found
$ exit