add a helper to make printing helptext on errors easier

cmd/lotus-storage-miner/main.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"fmt"
-	"os"
 
 	logging "github.com/ipfs/go-log/v2"
 	"github.com/urfave/cli/v2"
@@ -96,10 +95,7 @@ func main() {
 	app.Setup()
 	app.Metadata["repoType"] = repo.StorageMiner
 
-	if err := app.Run(os.Args); err != nil {
-		log.Warnf("%+v", err)
-		os.Exit(1)
-	}
+	lcli.RunApp(app)
 }
 
 func getActorAddress(ctx context.Context, nodeAPI api.StorageMiner, overrideMaddr string) (maddr address.Address, err error) {

cmd/lotus-storage-miner/sectors.go

@@ -251,15 +251,16 @@ var sectorsMarkForUpgradeCmd = &cli.Command{
 	Usage:     "Mark a committed capacity sector for replacement by a sector with deals",
 	ArgsUsage: "<sectorNum>",
 	Action: func(cctx *cli.Context) error {
+		if cctx.Args().Len() != 1 {
+			return lcli.ShowHelp(cctx, xerrors.Errorf("must pass sector number"))
+		}
+
 		nodeApi, closer, err := lcli.GetStorageMinerAPI(cctx)
 		if err != nil {
 			return err
 		}
 		defer closer()
 		ctx := lcli.ReqContext(cctx)
-		if cctx.Args().Len() != 1 {
-			return xerrors.Errorf("must pass sector number")
-		}
 
 		id, err := strconv.ParseUint(cctx.Args().Get(0), 10, 64)
 		if err != nil {