shellex: fix aliasing and colorize grep

shellex/apis/tty.lua

@@ -8,12 +8,23 @@ local cmap = {
   [ 0x44CC00 ] = colors.lime,
   [ 0xB0B00F ] = colors.yellow,
   [ 0xFFFFFF ] = colors.white,
+
+  [ 0xb000b0 ] = colors.purple,
+  [ 0x00FF00 ] = colors.green,
+  [ 0xFF0000 ] = colors.red,
+  [ 0x00FFFF ] = colors.cyan,
+  [ 0x000000 ] = colors.black,
 }
 
 return {
   gpu = function()
+    local current = 0xFFFFFF
     return {
-      setForeground = function(c) term.setTextColor(cmap[c]) end,
+      setForeground = function(c)
+        current = c
+        term.setTextColor(cmap[c])
+      end,
+      getForeground = function() return current end,
     }
   end,
   getViewport = term.getSize,