Path and Walk

Command.Path() returns the list of command names from the root to the current command. Command.Walk() visits a command and every subcommand recursively, calling a function on each.

Path

The Path() method returns []string where each element is a Command.Name starting from the root. FullName() is equivalent to strings.Join(cmd.Path(), " ").

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/urfave/cli/v3"
)

func main() {
	subSubCmd := &cli.Command{Name: "bottom", Action: func(context.Context, *cli.Command) error { return nil }}
	subCmd := &cli.Command{Name: "mid", Subcommands: []*cli.Command{subSubCmd}, Action: func(context.Context, *cli.Command) error { return nil }}
	cmd := &cli.Command{
		Name: "top",
		Subcommands: []*cli.Command{subCmd},
		Action: func(ctx context.Context, c *cli.Command) error {
			fmt.Println(strings.Join(c.Path(), " "))
			return nil
		},
	}

	cmd.Run(context.Background(), []string{"top", "mid", "bottom"})
}

sh-session

$ go run .
top mid bottom

Walk

Walk() traverses the command tree depth-first, visiting the command itself first, then each subcommand recursively.

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/urfave/cli/v3"
)

func main() {
	subSubCmd := &cli.Command{Name: "bottom", Action: func(context.Context, *cli.Command) error { return nil }}
	subCmd := &cli.Command{Name: "mid", Subcommands: []*cli.Command{subSubCmd}, Action: func(context.Context, *cli.Command) error { return nil }}
	cmd := &cli.Command{
		Name: "top",
		Subcommands: []*cli.Command{subCmd},
		Action: func(ctx context.Context, c *cli.Command) error { return nil },
	}

	cmd.Walk(func(c *cli.Command) error {
		fmt.Println(c.Name)
		return nil
	})
}

sh-session

$ go run .
top
mid
bottom

Short-circuiting

Return a non-nil error from the walk function to stop traversal early.

package main

import (
	"errors"
	"fmt"
	"os"

	"github.com/urfave/cli/v3"
)

func main() {
	subSubCmd := &cli.Command{Name: "bottom", Action: func(context.Context, *cli.Command) error { return nil }}
	subCmd := &cli.Command{Name: "mid", Subcommands: []*cli.Command{subSubCmd}, Action: func(context.Context, *cli.Command) error { return nil }}
	cmd := &cli.Command{
		Name: "top",
		Subcommands: []*cli.Command{subCmd},
		Action: func(ctx context.Context, c *cli.Command) error { return nil },
	}

	err := cmd.Walk(func(c *cli.Command) error {
		fmt.Println(c.Name)
		if c.Name == "mid" {
			return errors.New("stop")
		}
		return nil
	})
	fmt.Println(err)
}

sh-session

$ go run .
top
mid
stop

Relation to Lineage

Lineage() returns the command and all its ancestors as []*Command (child first). Path() is similar but returns only the command names as []string (root first). Use Lineage() when you need access to the ancestor *Command values; use Path() when you only need the names.