tb %PID builtin command

user/tb/runtime.c

@@ -4,6 +4,8 @@
 #include "runtime.h"
 #include "interp.h"
 
+extern PID_t PID;
+
 RtCmd *RTCMDS = NULL;
 RtAlias *RTALIASES = NULL;
 
@@ -45,7 +47,13 @@ bool rt_mkalias(Token *tks) {
   return true;
 }
 
+bool rt_PID(Token *tks) {
+  uprintf("%lu\n", PID);
+  return true;
+}
+
 void rt_init(void) {
   RTCMD("%print", &rt_print);
   RTCMD("%mkalias", &rt_mkalias);
+  RTCMD("%PID", &rt_PID);
 }