Toolchain: Build, Check, Ship

Sun, 04 Oct 2026 00:00:00 +0000

One binary ships with the language and covers dependency management, building, testing, formatting and static checks. ./... means “this package and everything below it”.

The `go` command

Task	Command
Create a project	`go mod init example.com/app`
Add a dependency	`go get github.com/x/y@v1.4.0`
Sync deps with imports	`go mod tidy`
Why is a dep here?	`go mod why -m github.com/x/y`
Run without building	`go run ./cmd/server`
Build a binary	`go build -o bin/app ./cmd/server`
Install a CLI tool	`go install github.com/air-verse/air@latest`
Pin a dev tool in the project	`go get -tool ...` → `go tool ...`
Test	`go test ./...`
Format	`gofmt -w .` / `go fmt ./...`
Static checks	`go vet ./...`
Docs in the terminal	`go doc net/http.ServeMux`
Multi-module workspace	`go work init ./svc-a ./svc-b`
Generate code	`go generate ./...`

Modules

go.mod declares the module path, Go version and direct dependencies; go.sum pins checksums. Commit both.
The go line is the minimum language version; a toolchain line can require a newer toolchain, which is downloaded automatically.
Major versions ≥ 2 are part of the import path: github.com/jackc/pgx/v5.

Build

# Cross-compile: just set two env vars
GOOS=linux GOARCH=arm64 go build -o bin/app-linux-arm64 ./cmd/server

# Static, reproducible, stripped, with an injected version
CGO_ENABLED=0 go build -trimpath \
  -ldflags="-s -w -X main.version=1.4.2" -o bin/app ./cmd/server

Flag	Effect
`CGO_ENABLED=0`	No libc dependency → fully static, runs on `scratch` / distroless
`-trimpath`	Removes local file paths from the binary
`-ldflags="-s -w"`	Strips symbol table and DWARF (smaller binary)
`-X pkg.var=value`	Sets a string variable at link time

go version -m bin/app shows the module versions and build settings baked into any Go binary.

Docker on Notes

Toolchain: Build, Check, Ship

The go command

Modules

Build

The `go` command