tests clear

main.go

@@ -95,6 +95,9 @@ func foundOne(ctx context.Context, outd, inf string, fields Fields, mvNLn MvNLn)
 }
 
 func RealMvNLn(outf, inf string) error {
+	if stat, err := os.Stat(inf); err != nil || !stat.Mode().IsRegular() {
+		return fmt.Errorf("cannot mv_n_ln(%s): (%v) mode=%v", inf, err, stat.Mode())
+	}
 	if _, err := os.Stat(outf); err == nil {
 		return nil // fmt.Errorf("conflict: %s already exists", path.Base(outf))
 	}