flag包使用详解

##概述 flag包提供了一系列解析命令行参数的功能接口

###Variables

var (
  CommandLine = NewFlagSet(os.Args[0], ExitOnError)
  ErrHelp     = errors.New("flag: help requested")
  Usage       = func() {
    fmt.Fprintf(os.Stderr, "Usage of %s:\n", os.Args[0])
    PrintDefaults()
  }
)

##包函数列表

• func Arg(i int) string
• func Args() []string
• func Bool(name string, value bool, usage string) *bool
• func BoolVar(p *bool, name string, value bool, usage string)
• func Duration(name string, value time.Duration, usage string) *time.Duration
• func DurationVar(p *time.Duration, name string, value time.Duration, usage string)
• func Float64(name string, value float64, usage string) *float64
• func Float64Var(p *float64, name string, value float64, usage string)
• func Int(name string, value int, usage string) *int
• func Int64(name string, value int64, usage string) *int64
• func Int64Var(p *int64, name string, value int64, usage string)
• func IntVar(p *int, name string, value int, usage string)
• func NArg() int
• func NFlag() int
• func Parse()
• func Parsed() bool
• func PrintDefaults()
• func Set(name, value string) error
• func String(name string, value string, usage string) *string
• func StringVar(p *string, name string, value string, usage string)
• func Uint(name string, value uint, usage string) *uint
• func Uint64(name string, value uint64, usage string) *uint64
• func Uint64Var(p *uint64, name string, value uint64, usage string)
• func UintVar(p *uint, name string, value uint, usage string)
• func Var(value Value, name string, usage string)
• func Visit(fn func(*Flag))
• func VisitAll(fn func(*Flag))

type Flag

type Flag struct {
        Name     string // name as it appears on command line
        Usage    string // help message
        Value    Value  // value as set
        DefValue string // default value (as text); for usage message
}

• func Lookup(name string) *Flag

type FlagSet

type FlagSet struct {
        Usage func()
}

• func NewFlagSet(name string, errorHandling ErrorHandling) *FlagSet
• func (f *FlagSet) Arg(i int) string
• func (f *FlagSet) Args() []string
• func (f *FlagSet) Bool(name string, value bool, usage string) *bool
• func (f *FlagSet) BoolVar(p *bool, name string, value bool, usage string)
• func (f *FlagSet) Duration(name string, value time.Duration, usage string) *time.Duration
• func (f *FlagSet) DurationVar(p *time.Duration, name string, value time.Duration, usage string)
• func (f *FlagSet) Float64(name string, value float64, usage string) *float64
• func (f *FlagSet) Float64Var(p *float64, name string, value float64, usage string)
• func (f *FlagSet) Init(name string, errorHandling ErrorHandling)
• func (f *FlagSet) Int(name string, value int, usage string) *int
• func (f *FlagSet) Int64(name string, value int64, usage string) *int64
• func (f *FlagSet) Int64Var(p *int64, name string, value int64, usage string)
• func (f *FlagSet) IntVar(p *int, name string, value int, usage string)
• func (f *FlagSet) Lookup(name string) *Flag
• func (f *FlagSet) NArg() int
• func (f *FlagSet) NFlag() int
• func (f *FlagSet) Parse(arguments []string) error
• func (f *FlagSet) Parsed() bool
• func (f *FlagSet) PrintDefaults()
• func (f *FlagSet) Set(name, value string) error
• func (f *FlagSet) SetOutput(output io.Writer)
• func (f *FlagSet) String(name string, value string, usage string) *string
• func (f *FlagSet) StringVar(p *string, name string, value string, usage string)
• func (f *FlagSet) Uint(name string, value uint, usage string) *uint
• func (f *FlagSet) Uint64(name string, value uint64, usage string) *uint64
• func (f *FlagSet) Uint64Var(p *uint64, name string, value uint64, usage string)
• func (f *FlagSet) UintVar(p *uint, name string, value uint, usage string)
• func (f *FlagSet) Var(value Value, name string, usage string)
• func (f *FlagSet) Visit(fn func(*Flag))
• func (f *FlagSet) VisitAll(fn func(*Flag))

type Getter

type Getter interface {
        Value
        Get() interface{}
}

type Value

type Value interface {
        String() string
        Set(string) error
}