fix default flag behaviour in du command (#3031)

- `mc du` without args should print help like other `mc` commands
- `mc du` should behave like `du -h --max-depth=1` as default
- optional `--recursive` if they want capacity for each folder.
fixes #2871

cmd/du-main.go

@@ -36,6 +36,10 @@ var (
  Name: "depth, d",
  Usage: "print the total for a folder prefix only if it is N or fewer levels below the command line argument",
  },
+ cli.BoolFlag{
+ Name: "recursive, r",
+ Usage: "recursively print the total for a folder prefix",
+ },
  }
 )
 
@@ -153,6 +157,10 @@ func du(urlStr string, depth int, encKeyDB map[string][]prefixSSEPair) (int64, e
 
 // main for du command.
 func mainDu(ctx *cli.Context) error {
+ if !ctx.Args().Present() {
+ cli.ShowCommandHelpAndExit(ctx, "du", 1)
+ }
+
  console.SetColor("Prefix", color.New(color.FgCyan, color.Bold))
  console.SetColor("Size", color.New(color.FgYellow))
 
@@ -163,7 +171,13 @@ func mainDu(ctx *cli.Context) error {
  // du specific flags.
  depth := ctx.Int("depth")
  if depth == 0 {
- depth = -1
+ if ctx.Bool("recursive") {
+ if !ctx.IsSet("depth") {
+ depth = -1
+ }
+ } else {
+ depth = 1
+ }
  }
 
  // Set color.