help

func BuildArgUsage ¶

func BuildArgUsage(args []cli.ArgDef) string

BuildArgUsage builds the argument usage string (e.g., "<required> [optional...]").

func CommandPath ¶

func CommandPath(chain []cli.Commander) string

CommandPath builds the full command path from a chain (e.g., "app sub1 sub2").

func Compact ¶

func Compact(opts ...Option) cli.HelpRenderer

Compact returns a help renderer that produces dense, minimal output.

Example output:

myapp serve - Start the HTTP server
Usage: myapp serve [flags]
Commands: start, stop, status
Flags:
  -p, --port int     Port (default: 8080)
  -v, --verbose      Enable verbose output

func Default ¶

func Default(opts ...Option) cli.HelpRenderer

Default returns a help renderer that matches the built-in cli help output. It supports optional color output, sorting, and width configuration.

func FlagLeft ¶

func FlagLeft(f *cli.FlagDef) string

FlagLeft builds the left column for a flag (e.g., "-v, --verbose").

func FlagRight ¶

func FlagRight(f *cli.FlagDef) string

FlagRight builds the right column for a flag (description, default, etc.).

func HasVisibleFlags ¶

func HasVisibleFlags(flags []cli.FlagDef) bool

HasVisibleFlags returns true if any flag is not hidden.

func InterpolateHelp ¶

func InterpolateHelp(help, def, mask, enum, env string) string

InterpolateHelp replaces ${default}, ${enum}, and ${env} placeholders in help text.

func JSON ¶

func JSON(opts ...Option) cli.HelpRenderer

JSON returns a help renderer that produces machine-readable JSON output. This is useful for programmatic consumption, documentation generation, or integration with other tools.

func Man ¶

func Man(opts ...Option) cli.HelpRenderer

Man returns a help renderer that produces man page style output.

Example output:

NAME
    myapp serve - Start the HTTP server

SYNOPSIS
    myapp serve [flags]

DESCRIPTION
    Extended description here.

OPTIONS
    -p, --port int
        Port to listen on. Default: 8080

func Markdown ¶

func Markdown(opts ...Option) cli.HelpRenderer

Markdown returns a help renderer that produces Markdown format output. This is useful for generating documentation or rendering help in Markdown-aware environments.

Example output:

# myapp serve

Start the HTTP server.

## Usage

    myapp serve [flags]

## Flags

| Flag | Type | Default | Description |
|------|------|---------|-------------|
| `-p, --port` | int | 8080 | Port to listen on |

func MaxCommandWidth ¶

func MaxCommandWidth(subs []cli.Commander) int

MaxCommandWidth calculates the maximum name width across commands.

func MaxFlagWidth ¶

func MaxFlagWidth(flags []cli.FlagDef) int

MaxFlagWidth calculates the maximum left column width across flags.

func MustTemplate ¶

func MustTemplate(tmplStr string, opts ...Option) cli.HelpRenderer

MustTemplate is like Template but panics if the template cannot be parsed. Use this for templates that are compile-time constants where parse errors indicate programmer error. For templates loaded at runtime, use Template and handle the error explicitly.

func MustTemplateFile ¶

func MustTemplateFile(path string, opts ...Option) cli.HelpRenderer

MustTemplateFile is like TemplateFile but panics if the file cannot be read or the template cannot be parsed. Use this for templates that are bundled with your application where errors indicate programmer error. For user-provided template files, use TemplateFile and handle errors.

func ResolveWidth ¶

func ResolveWidth(opts *Options) int

ResolveWidth returns the configured width or auto-detects.

func Template ¶

func Template(tmplStr string, opts ...Option) (cli.HelpRenderer, error)

Template returns a help renderer using a Go text/template string. The template receives a Data struct as its data context.

Available template functions:

• join: strings.Join
• upper: strings.ToUpper
• lower: strings.ToLower
• title: strings.Title (deprecated but commonly expected)
• indent: indents each line by n spaces
• wrap: wraps text to n columns
• default: returns fallback if value is empty
• repeat: repeats a string n times
• trimPrefix: strings.TrimPrefix
• trimSuffix: strings.TrimSuffix
• contains: strings.Contains
• hasPrefix: strings.HasPrefix
• hasSuffix: strings.HasSuffix
• replace: strings.ReplaceAll

func TemplateFile ¶

func TemplateFile(path string, opts ...Option) (cli.HelpRenderer, error)

TemplateFile returns a help renderer using a template file. The template receives a Data struct as its data context.

func Tree ¶

func Tree(opts ...Option) cli.HelpRenderer

Tree returns a help renderer that displays command hierarchy as an ASCII tree.

Example output:

myapp
├── serve       Start the server
│   ├── --port int     Port (default: 8080)
│   └── --verbose      Enable verbose output
├── deploy      Deploy the application
│   ├── prod    Deploy to production
│   └── staging Deploy to staging
└── status      Show status

func VisibleFlags ¶

func VisibleFlags(flags []cli.FlagDef) []cli.FlagDef

VisibleFlags filters out hidden flags.

func VisibleSubcommands ¶

func VisibleSubcommands(subs []cli.Commander) []cli.Commander

VisibleSubcommands filters out hidden subcommands.

func Wrap ¶

func Wrap(text string, width int) string

Wrap wraps text to the specified width.