// Minimal test shell to verify the execution environment
#include <stddef.h>

extern int write(int fd, const void *buf, size_t count);
extern int read(int fd, void *buf, size_t count);

int main(int argc, char *argv[], char *envp[]) {
    const char *prompt = "shell> ";
    char buf[128];
    
    while (1) {
        // Print prompt
        write(1, prompt, 7);
        
        // Read command
        int n = read(0, buf, sizeof(buf) - 1);
        if (n <= 0) continue;
        
        buf[n] = '\0';
        
        // Echo back
        write(1, "You typed: ", 11);
        write(1, buf, n);
        
        // Check for exit
        if (buf[0] == 'q' && buf[1] == '\n') {
            write(1, "Goodbye!\n", 9);
            break;
        }
    }
    
    return 0;
}