Added backspace support for the interactive shell, updated it behavior slightly.

src/scrn.c

@@ -86,6 +86,8 @@ void putch(unsigned char c)
     if(c == 0x08)
     {
         if(csr_x != 0) csr_x--;
+        where = textmemptr + (csr_y * 80 + csr_x);
+        *where = ' ' | att;	/* Character AND attributes: color */
     }
     /* Handles a tab by incrementing the cursor's x, but only
     *  to a point that will make it divisible by 8 */

src/shell.c

@@ -15,16 +15,34 @@ void run_shell()
 void key_pressed(unsigned char* character)
 {
 	int len = strlen(commandbuffer);
-	commandbuffer[len] = character;
-	commandbuffer[len + 1] = '\0';
+	//Check to see if the backspace has been pressed.
+	if(character != '\b')
+	{
+		//If it has not then simply add the character
+		//to the commandbuffer, and don't forget the null byte.
+		commandbuffer[len] = character;
+		commandbuffer[len + 1] = '\0';		
+	}
+	else
+	{
+		//Otherwise clear the last character from the command
+		//buffer.
+		commandbuffer[len - 1] = '\0';
+	}
+
 	putch(character);
 }
 
 void execmd()
 {
+	if(strlen(commandbuffer) == 0)
+	{
+		puts("\n#>");
+		return;
+	}
 	if(strcmp(commandbuffer, "version"))
 	{
-		puts("\nInteractive Shell Version 0.0.0.1\n");
+		puts("\nInteractive Shell Version 0.0.1.2\n");
 	}
 	else if(strcmp(commandbuffer,"cls"))
 	{
@@ -32,7 +50,9 @@ void execmd()
 	}
 	else
 	{
-		puts("\nUnknown command\n");
+		puts("\nUnknown command: ");
+		puts(commandbuffer);
+		puts(".\n");
 	}
 	puts("#>");
 	commandbuffer[0] = '\0';