* new command "status" to display current status of an app
* new batch mode (environment BATCH=1) which enables different exit codes for
  easier integration into scripts.
  steamcmd will exit with exit code = 4 if an app needs updating (status command)
  or an app has been updated (update command).
--- steamcmd.old/main.cpp	2012-08-26 00:00:12.000000000 +0200
+++ steamcmd/main.cpp	2012-08-27 17:23:36.000000000 +0200
@@ -7,6 +7,7 @@
 
 #include <stdarg.h>
 #include <math.h>
+#include <stdlib.h>
 
 #include "CCommandLine.h"
 
@@ -21,6 +22,9 @@
 	#define strcasecmp	_stricmp
 #endif
 
+#define EXIT_GAME_UPDATED      (1 << 2)
+#define EXIT_UPDATE_RELEASED   EXIT_GAME_UPDATED
+
 IClientEngine* g_pClientEngine = NULL;
 IClientUser* g_pClientUser = NULL;
 IClientAppManager* g_pClientAppManager = NULL;
@@ -63,6 +67,7 @@
 	void ProgressMsg(const char* cszFormat, ...);
 	bool m_bWasProgressMsg;
 	unsigned int m_uLastProgressMsgSize;
+	bool m_batch;
 
 	CCommandLine commandLine;
 
@@ -140,6 +145,10 @@
 
 void CApplication::Exit(int iCode)
 {
+	/* convert to failure/success exit codes only in non-batch mode (-autoupdate requirement) */
+	if (!m_batch && iCode != EXIT_FAILURE)
+		iCode = EXIT_SUCCESS;
+
 	if(m_bWaitingForCredentials && g_pClientUser->BLoggedOn())
 	{
 		Msg("Waiting for credentials to cache.\n");
@@ -218,7 +227,7 @@
 			ShowAvailableApps();
 			this->Exit(EXIT_SUCCESS);
 		}
-		else if(strcasecmp(cszCommand, "update") == 0)
+		else if(strcasecmp(cszCommand, "update") == 0 || strcasecmp(cszCommand, "status") == 0)
 		{
 			Msg("Requesting appinfo update.\n");
 
@@ -265,7 +274,7 @@
 				Msg("Up to date.\n", m_uInstallingAppId);
 				m_uInstallingAppId = k_uAppIdInvalid;
 				g_pClientAppManager->SetDownloadingEnabled(false);
-				this->Exit(EXIT_SUCCESS);
+				this->Exit(EXIT_GAME_UPDATED);
 			}
 		}
 	}
@@ -389,14 +398,20 @@
 	m_bWasProgressMsg = false;
 	m_uInstallingAppId = k_uAppIdInvalid;
 	m_uUninstallingAppId = k_uAppIdInvalid;
+
+	char *batch = getenv("BATCH");
+	m_batch = (batch != NULL && strcmp(batch, "1") == 0);
 }
 
 void CApplication::OnAppInfoUpdateComplete(AppInfoUpdateComplete_t* pParam)
 {
-	if(m_bWaitingForAppInfoUpdate && strcasecmp(commandLine.ParmValue("-command", ""), "update") == 0)
-	{
-		m_bWaitingForAppInfoUpdate = false;
+	if (!m_bWaitingForAppInfoUpdate)
+		return;
+	m_bWaitingForAppInfoUpdate = false;
 
+	const char* cszCommand = commandLine.ParmValue("-command");
+	if(strcasecmp(cszCommand, "update") == 0)
+	{
 		AppId_t uAppId = commandLine.ParmValue("-game", (int)k_uAppIdInvalid);
 
 		bool bVerifyAll = commandLine.FindParm("-verify_all") != 0;
@@ -406,6 +421,22 @@
 		else if(eResult == k_EUpdateResultAlreadyUpToDate)
 			this->Exit(EXIT_SUCCESS);
 	}
+	else if(strcasecmp(cszCommand, "status") == 0)
+	{
+		AppId_t uAppId = commandLine.ParmValue("-game", (int)k_uAppIdInvalid);
+
+		if(g_pClientAppManager->GetAppInstallState(uAppId) & k_EAppStateUninstalled)
+		{
+			Error("This app (%u:%s) isn't installed\n", uAppId, GetAppName(uAppId));
+			this->Exit(EXIT_FAILURE);
+		}
+		else
+		{
+			bool uptodate = g_pClientAppManager->BIsAppUpToDate(uAppId);
+			Msg("%u:%s %s\n", uAppId, GetAppName(uAppId), (uptodate) ? "is up to date" : "needs updating");
+			this->Exit((uptodate) ? EXIT_SUCCESS : EXIT_UPDATE_RELEASED);
+		}
+	}
 }
 
 void CApplication::OnDisconnected(SteamServersDisconnected_t* pParam)
@@ -728,6 +759,7 @@
 			"   update: Install or update a game\n"
 			"   uninstall: Remove a game\n"
 			"   list: View available games and their status\n"
+			"   status: View status of a game\n"
 			"\n"
 			"Parameters:\n"
 			"   -game <appid>             -   Game AppID to install / update / uninstall\n"
@@ -797,13 +829,14 @@
 		return false;
 	}
 
-	if(strcasecmp(cszCommand, "list") != 0 && strcasecmp(cszCommand, "update") != 0 && strcasecmp(cszCommand, "uninstall") != 0)
+	if(strcasecmp(cszCommand, "list") != 0 && strcasecmp(cszCommand, "update") != 0 && strcasecmp(cszCommand, "uninstall") != 0
+			&& strcasecmp(cszCommand, "status") != 0)
 	{
 		Error("Invalid command specified.\n");
 		return false;
 	}
 
-	if(strcasecmp(cszCommand, "update") == 0 || strcasecmp(cszCommand, "uninstall") == 0)
+	if(strcasecmp(cszCommand, "update") == 0 || strcasecmp(cszCommand, "uninstall") == 0 || strcasecmp(cszCommand, "status") == 0)
 	{
 		if(commandLine.FindParm("-game") == 0)
 		{
@@ -829,6 +862,12 @@
 		return false;
 	}
 
+	if (m_batch && commandLine.FindParm("-autoupdate") != 0)
+	{
+		Msg("Batch mode and -autoupdate is mutually exclusive. Disabling batch mode...\n");
+		m_batch = false;
+	}
+
 	return true;
 }