diff --git a/source/src/command.cpp b/source/src/command.cpp
index 6f6b87f0..9b30ee7c 100644
--- a/source/src/command.cpp
+++ b/source/src/command.cpp
@@ -496,7 +496,7 @@ char *conc(const char **w, int n, bool space)
         r += wlen[i];
         if(space) *r++ = ' ';
     }
-    if(space) --r;
+    if(space && n) --r;
     *r = '\0';
     return res;
 }