SERVER-3112: Improved stdout/err in mongoexport

1 files changed, 13 insertions, 0 deletions

diff --git a/tools/export.cpp b/tools/export.cpp
index c3a5420438d..0d9f0225da0 100644
--- a/tools/export.cpp
+++ b/tools/export.cpp
@@ -45,6 +45,19 @@ public:
         _usesstdout = false;
     }
 
+    virtual void preSetup() {
+        string out = getParam("out");
+        if ( out == "-" ) {
+                // write output to standard error to avoid mangling output
+                // must happen early to avoid sending junk to stdout
+                useStandardOutput(false);
+        }
+    }
+
+    virtual void printExtraHelp( ostream & out ) {
+        out << "Export MongoDB data to CSV, TSV or JSON files.\n" << endl;
+    }
+
     // Turn every double quote character into two double quote characters
     // If hasSurroundingQuotes is true, doesn't escape the first and last
     // characters of the string, if it's false, add a double quote character