Explain Go modules and dependency management.

Go Modules: • Dependency management system (Go 1.11+) • go.mod file defines module • Semantic versioning • Minimal version selection • Replace and exclude directives Commands: • go mod init: Initialize module • go mod tidy: Clean dependencies • go mod download: Download dependencies • go mod vendor: Create vendor directory go.mod example: module github.com/user/project go 1.19 require ( github.com/gorilla/mux v1.8.0 golang.org/x/crypto v0.0.0-20220525230936-793ad666bf5e ) replace github.com/old/package => github.com/new/package v1.0.0