4 files changed, 9 insertions, 1 deletions
diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc
index 92349488e7..24bedb3fb6 100644
--- a/src/libmain/shared.cc
+++ b/src/libmain/shared.cc
@@ -51,6 +51,8 @@ static void initAndRun(int argc, char * * argv)
         string arg = *i;
         if (arg == "--verbose" || arg == "-v")
             verbosity = (Verbosity) ((int) verbosity + 1);
+        else if (arg == "--build-output" || arg == "-B")
+            buildVerbosity = lvlError; /* lowest */
         else if (arg == "--help") {
             printHelp();
             return;
diff --git a/src/libstore/exec.cc b/src/libstore/exec.cc
index 2adf03841c..b25423b444 100644
--- a/src/libstore/exec.cc
+++ b/src/libstore/exec.cc
@@ -22,7 +22,7 @@ void runProgram(const string & program,
 {
     /* Create a log file. */
     string logCommand = 
-	verbosity >= lvlDebug 
+	verbosity >= buildVerbosity 
 	? "tee "  + logFileName + " >&2"
 	: "cat > " + logFileName;
     /* !!! auto-pclose on exit */
diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
index e5d76ff485..b3c658c295 100644
--- a/src/libstore/globals.cc
+++ b/src/libstore/globals.cc
@@ -7,3 +7,5 @@ string nixStateDir = "/UNINIT";
 string nixDBPath = "/UNINIT";
 
 bool keepFailed = false;
+
+Verbosity buildVerbosity = lvlDebug;
diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
index 3da294cc82..5d5e9efcfe 100644
--- a/src/libstore/globals.hh
+++ b/src/libstore/globals.hh
@@ -2,6 +2,7 @@
 #define __GLOBALS_H
 
 #include <string>
+#include "util.hh"
 
 using namespace std;
 
@@ -28,5 +29,8 @@ extern string nixDBPath;
 /* Whether to keep temporary directories of failed builds. */
 extern bool keepFailed;
 
+/* Verbosity level for build output. */
+extern Verbosity buildVerbosity;
+
 
 #endif /* !__GLOBALS_H */