Allows command suggestions along with "unknown command" errors

command.go

@@ -106,6 +106,11 @@ type Command struct {
 	helpCommand   *Command                 // The help command
 	// The global normalization function that we can use on every pFlag set and children commands
 	globNormFunc func(f *flag.FlagSet, name string) flag.NormalizedName
+
+	// Disable the suggestions based on Levenshtein distance that go along with 'unknown command' messages
+	DisableSuggestions bool
+	// If displaying suggestions, allows to set the minimum levenshtein distance to display, must be > 0
+	SuggestionsMinimumDistance int
 }
 
 // os.Args[1:] by default, if desired, can be overridden
@@ -419,9 +424,31 @@ func (c *Command) Find(args []string) (*Command, []string, error) {
 	if !commandFound.HasSubCommands() {
 		return commandFound, a, nil
 	}
+
 	// root command with subcommands, do subcommand checking
 	if commandFound == c && len(argsWOflags) > 0 {
-		return commandFound, a, fmt.Errorf("unknown command %q for %q", argsWOflags[0], commandFound.CommandPath())
+		suggestions := ""
+		if !c.DisableSuggestions {
+			if c.SuggestionsMinimumDistance <= 0 {
+				c.SuggestionsMinimumDistance = 2
+			}
+			similar := []string{}
+			for _, cmd := range c.commands {
+				if cmd.IsAvailableCommand() {
+					levenshtein := ld(argsWOflags[0], cmd.Name(), true)
+					if levenshtein <= c.SuggestionsMinimumDistance {
+						similar = append(similar, cmd.Name())
+					}
+				}
+			}
+			if len(similar) > 0 {
+				suggestions += "\n\nDid you mean this?\n"
+				for _, s := range similar {
+					suggestions += fmt.Sprintf("\t%v\n", s)
+				}
+			}
+		}
+		return commandFound, a, fmt.Errorf("unknown command %q for %q%s", argsWOflags[0], commandFound.CommandPath(), suggestions)
 	}
 
 	return commandFound, a, nil