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Golang CLI development — command structure, flags, config layering, exit codes, I/O, signals, shell completion, validation, testing. Use when building or reviewing a Go CLI or code using cobra, viper, urfave/cli. Cobra → `golang-spf13-cobra`; viper → `golang-spf13-viper`.
默认使用会先检查来源的 Prompt；你也可以切换为直接命令，或下载本地副本。
决定是否安装前，请先阅读 SKILL.md，以及 SkillsMP 当前展示的配套文件。
用 Codex 或 Claude 帮你安装 复制这段 Prompt，粘贴到 Codex、Claude 或其他助手里，让它检查 Skill 页面并帮你完成安装。
直接命令不会经过审查 Prompt；运行前请先检查来源。
npx skills add https://github.com/context-labs/whip --skill golang-cli命令会保持在同一行。复制前请横向滚动并检查完整内容。
想先保存到本地？可下载 SkillsMP 当前能够提供的文件。
正在显示 SKILL.md
基于 SOC 职业分类
| name | golang-cli |
| description | Golang CLI development — command structure, flags, config layering, exit codes, I/O, signals, shell completion, validation, testing. Use when building or reviewing a Go CLI or code using cobra, viper, urfave/cli. Cobra → `golang-spf13-cobra`; viper → `golang-spf13-viper`. |
| user-invocable | true |
| license | MIT |
| compatibility | Designed for Claude Code, Codex or similar harness, and for projects using Golang. |
| metadata | {"author":"samber","version":"1.3.0","openclaw":{"emoji":"💻","homepage":"https://github.com/samber/cc-skills-golang","requires":{"bins":"[Truncated]"},"install":[]}} |
| allowed-tools | Read Edit Write Glob Grep Bash(go:*) Bash(golangci-lint:*) Bash(git:*) Agent AskUserQuestion |
| paths | ["**/*.go"] |
Persona: You are a Go CLI engineer. You build tools that feel native to the Unix shell — composable, scriptable, and predictable under automation.
Modes:
SilenceUsage/SilenceErrors, flag-to-Viper binding, exit codes, and stdout/stderr discipline.Use Cobra + Viper as the default stack for Go CLI applications. Cobra provides the command/subcommand/flag structure and Viper handles configuration from files, environment variables, and flags with automatic layering. This combination powers kubectl, docker, gh, hugo, and most production Go CLIs.
When using Cobra or Viper, refer to the library's official documentation and code examples for current API signatures.
For trivial single-purpose tools with no subcommands and few flags, stdlib flag is sufficient.
| Concern | Package / Tool |
|---|---|
| Commands & flags | github.com/spf13/cobra |
| Configuration | github.com/spf13/viper |
| Flag parsing | github.com/spf13/pflag (via Cobra) |
| Colored output | github.com/fatih/color |
| Table output | github.com/olekukonko/tablewriter |
| Interactive prompts | github.com/charmbracelet/bubbletea |
| Version injection | go build -ldflags |
| Distribution | goreleaser |
Organize CLI commands in cmd/myapp/ with one file per command. Keep main.go minimal — it only calls Execute().
myapp/
├── cmd/
│ └── myapp/
│ ├── main.go # package main, only calls Execute()
│ ├── root.go # Root command + Viper init
│ ├── serve.go # "serve" subcommand
│ ├── migrate.go # "migrate" subcommand
│ └── version.go # "version" subcommand
├── go.mod
└── go.sum
main.go should be minimal — see assets/examples/main.go.
The root command initializes Viper configuration and sets up global behavior via PersistentPreRunE. See assets/examples/root.go.
Key points:
SilenceUsage: true MUST be set — prevents printing the full usage text on every errorSilenceErrors: true MUST be set — lets you control error output format yourselfPersistentPreRunE runs before every subcommand, so config is always initializedAdd subcommands by creating separate files in cmd/myapp/ and registering them in init(). See assets/examples/serve.go for a complete subcommand example including command groups.
See assets/examples/flags.go for all flag patterns:
--config)--port)Use MarkFlagRequired, MarkFlagsMutuallyExclusive, and MarkFlagsOneRequired for flag constraints.
Provide completion suggestions for flag values.
This ensures viper.GetInt("port") returns the flag value, env var MYAPP_PORT, or config file value — whichever has highest precedence.
Cobra provides built-in validators for positional arguments. See assets/examples/args.go for both built-in and custom validation examples.
| Validator | Description |
|---|---|
cobra.NoArgs | Fails if any args provided |
cobra.ExactArgs(n) | Requires exactly n args |
cobra.MinimumNArgs(n) | Requires at least n args |
cobra.MaximumNArgs(n) | Allows at most n args |
cobra.RangeArgs(min, max) | Requires between min and max |
cobra.ExactValidArgs(n) | Exactly n args, must be in ValidArgs |
Viper resolves configuration values in this order (highest to lowest precedence):
See assets/examples/config.go for complete Viper integration including struct unmarshaling and config file watching.
port: 8080
host: localhost
log-level: info
database:
dsn: postgres://localhost:5432/myapp
max-conn: 25
With the setup above, these are all equivalent:
--port 9090MYAPP_PORT=9090port: 9090Version SHOULD be embedded at compile time using ldflags. See assets/examples/version.go for the version command and build instructions.
Exit codes MUST follow Unix conventions:
| Code | Meaning | When to Use |
|---|---|---|
| 0 | Success | Operation completed normally |
| 1 | General error | Runtime failure |
| 2 | Usage error | Invalid flags or arguments |
| 64-78 | BSD sysexits | Specific error categories |
| 126 | Cannot execute | Permission denied |
| 127 | Command not found | Missing dependency |
| 128+N | Signal N | Terminated by signal (e.g., 130 = SIGINT) |
See assets/examples/exit_codes.go for a pattern mapping errors to exit codes.
See assets/examples/output.go for all I/O patterns:
os.ModeCharDevice on stdout--output flag for table/json/plain formatsfatih/color which auto-disables when output is not a terminalSignal handling MUST use signal.NotifyContext to propagate cancellation through context. See assets/examples/signal.go for graceful HTTP server shutdown.
Cobra generates completions for bash, zsh, fish, and PowerShell automatically. See assets/examples/completion.go for both the completion command and custom flag/argument completions.
Test commands by executing them programmatically and capturing output. See assets/examples/cli_test.go.
Use cmd.OutOrStdout() and cmd.ErrOrStderr() in commands (instead of os.Stdout / os.Stderr) so output can be captured in tests.
| Mistake | Fix |
|---|---|
Writing to os.Stdout directly | Tests can't capture output. Use cmd.OutOrStdout() which tests can redirect to a buffer |
Calling os.Exit() inside RunE | Cobra's error handling, deferred functions, and cleanup code never run. Return an error, let main() decide |
| Not binding flags to Viper | Flags won't be configurable via env/config. Call viper.BindPFlag for every configurable flag |
Missing viper.SetEnvPrefix | PORT collides with other tools. Use a prefix (MYAPP_PORT) to namespace env vars |
| Logging to stdout | Unix pipes chain stdout — logs corrupt the data stream for the next program. Logs go to stderr |
| Printing usage on every error | Full help text on every error is noise. Set SilenceUsage: true, save full usage for --help |
| Config file required | Users without a config file get a crash. Ignore viper.ConfigFileNotFoundError — config should be optional |
Not using PersistentPreRunE | Config initialization must happen before any subcommand. Use root's PersistentPreRunE |
| Hardcoded version string | Version gets out of sync with tags. Inject via ldflags at build time from git tags |
Not supporting --output format | Scripts can't parse human-readable output. Add JSON/table/plain for machine consumption |
See samber/cc-skills-golang@golang-project-layout, samber/cc-skills-golang@golang-dependency-injection, samber/cc-skills-golang@golang-testing, samber/cc-skills-golang@golang-design-patterns skills.