Cobra CLI Application Reference

Reference for building CLI applications with cobra. Covers the public API, common patterns, and best practices.

Sub-Resources

Load the reference that matches your task. When in doubt, load multiple references.

Keywords	Reference
Command, AddCommand, subcommand, root command, project structure, command fields, Use, Short, Long, Example, Aliases, Deprecated, Hidden, GroupID, Run, RunE	references/commands.md
flag, PersistentFlags, LocalFlags, required flag, flag group, required together, mutually exclusive, one required, repeated flag, count flag, string slice, TraverseChildren, MarkFlagRequired, MarkPersistentFlagRequired	references/flags.md
argument, positional arg, Args, NoArgs, ArbitraryArgs, MinimumNArgs, MaximumNArgs, ExactArgs, RangeArgs, OnlyValidArgs, NoDuplicateArgs, MatchAll, ValidArgs, ArgAliases, custom validator	references/arguments.md
hook, lifecycle, PreRun, PostRun, PersistentPreRun, PersistentPostRun, PreRunE, PostRunE, EnableTraverseRunHooks, execution order, inherited hooks	references/hooks.md
help, usage, template, SetHelpFunc, SetHelpTemplate, SetUsageFunc, SetUsageTemplate, version, SetVersionTemplate, help command, command grouping, GroupID, SetHelpCommandGroupId, SetCompletionCommandGroupId, ErrPrefix	references/help-usage.md
completion, shell completion, ValidArgs, ValidArgsFunction, CompletionFunc, RegisterFlagCompletionFunc, ShellCompDirective, NoFileCompletions, FixedCompletions, active help, AppendActiveHelp, GetActiveHelpConfig, CompletionOptions, completion command, bash, zsh, fish, powershell	references/completions.md
viper, config, OnInitialize, BindPFlag, config file, 12-factor, initConfig, AutomaticEnv	references/viper-integration.md

Quick Guide

• How do I create a command or subcommand? → references/commands.md
• How do I add flags (persistent, local, required, groups)? → references/flags.md
• How do I validate positional arguments? → references/arguments.md
• How do lifecycle hooks work (PreRun, PostRun, etc.)? → references/hooks.md
• How do I customize help/usage/version output? → references/help-usage.md
• How do I add shell completions? → references/completions.md
• How do I integrate with Viper for config? → references/viper-integration.md
• How do I make a kubectl-style plugin? → references/commands.md
• How do I add Active Help messages during completion? → references/completions.md
• How do I make flags required-together or mutually-exclusive? → references/flags.md

Cross-Project References

• For cobra internals (Command struct fields, ExecuteC dispatch, Find vs Traverse, flag resolution, completion engine, shell script generation, global state), use the cobra-dev skill.
• For pflag internals (flag set implementation, POSIX compliance, non-POSIX modes), use the carapace-dev skill → references/pflag.md.