add cli flag to disable automatic addition of missing mods

cmd/fml/fml.go

@@ -16,7 +16,7 @@ import (
 type config struct {
 	modsdir, infile, outfile string
 	mods                     modlist.Modlist
-	clobber                  bool
+	clobber, addmissing      bool
 }
 
 var cfg config
@@ -73,6 +73,12 @@ func main() {
 				Required: false,
 				Usage:    "overwrite specified infile",
 			},
+			&cli.BoolFlag{
+				Name:     "no-add-missing",
+				Aliases:  []string{"m"},
+				Required: false,
+				Usage:    "don't automatically add mods missing from infile",
+			},
 		},
 		Before: func(ctx *cli.Context) error {
 			// Setup logger
@@ -86,6 +92,7 @@ func main() {
 
 			// Bool flags
 			cfg.clobber = ctx.Bool("clobber")
+			cfg.addmissing = !ctx.Bool("no-add-missing")
 
 			// Deal with in/out file
 			var in = ctx.String("infile")
@@ -116,10 +123,13 @@ func main() {
 				return err
 			}
 
+			if cfg.addmissing {
 				err = modlist.AddModsNotInList(cfg.modsdir, &cfg.mods)
 				if err != nil {
 					return err
 				}
+			}
+
 			selected, err := prompt.Show(&cfg.mods)
 			if err != nil {
 				log.Fatal(err)