Added base Pish from slides and fixed Makefile

src/Pish.c

@@ -0,0 +1,42 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/wait.h>
+#include "Pish.h"
+
+// Dummy function for Pish to run
+char* getcmd(void)
+{
+    ;
+}
+
+// Dummy function for Pish to run
+void exec(char* command)
+{
+    ;
+}
+
+
+
+void Pish(void)
+{
+    while (1)
+    {
+        char *cmd = getcmd();
+        int retval = fork();
+        if (retval == 0)
+        {
+            // This is the child process
+            // Setup the child's process environment here
+            // E.g., where is standard I/O, how to handle signals?
+            exec(cmd);
+            // exec does not return if it succeeds
+            printf("ERROR: Could not execute %s\n", cmd);
+            exit(1);
+        } else {
+            // This is the parent process; Wait for the child to finish
+            int pid = retval;
+            wait(pid);
+        }
+    }
+}

src/main.c

@@ -1,6 +1,6 @@
-#include <stdio.h>
+#include "Pish.h"
 
 int main()
 {
-    printf("Hello world\n");
+    Pish();
 }