flag package flag package provides types and functions useful for working with command line flags. installation flag package is part of standard Go library at flag usage Simple usage of flag var variable_name = flag.Type("flag_name", "initial_value", "help_message") flag.Type defines the data type of flag flag.String(), Bool(), Int(), etc. flag_name is used from command line to pass value to flag. initial_value is used to initialize flag to some default value and help_message is used to provide help information to user.
json package json package is part of Go standard library. It providers useful types and functions that can be used to work with json data and Go data types. installation json package is part of standard Go library at encoding/json usage There are two main operation defined while working with json, Marshaling : Marshaling is conversion of Go data types to json. Unmarshaling : Converting json to Go data type.