diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index 7f41c79..f5271ea 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -957,6 +957,11 @@
 	}
     } while (trailarg != NULL);
 
+    // Don't do anything if there is no command as there isn't really anything
+    // useful in running "sh -c ''".  Avoids changing "prevcmd".
+    if (STRLEN(newcmd) == 0)
+	return;
+
     vim_free(prevcmd);
     prevcmd = newcmd;