func (c *Context) GlobalString(name string) string {
	return lookupString(name, c.globalSet)
}
Looks up the value of a global string flag, returns "" if no string flag exists
package cli
import (
	"errors"
	"flag"
	"strconv"
	"strings"
)
type Context struct {
	App       *App
	Command   Command
	flagSet   *flag.FlagSet
	globalSet *flag.FlagSet
	setFlags  map[string]bool
}
func NewContext(app *App, set *flag.FlagSet, globalSet *flag.FlagSet) *Context {
	return &Context{App: app, flagSet: set, globalSet: globalSet}
}
func (c *Context) Int(name string) int {
	return lookupInt(name, c.flagSet)
}
func (c *Context) Float64(name string) float64 {
	return lookupFloat64(name, c.flagSet)
}
func (c *Context) Bool(name string) bool {
	return lookupBool(name, c.flagSet)
}
func (c *Context) BoolT(name string) bool {
	return lookupBoolT(name, c.flagSet)
}
func (c *Context) String(name string) string {
	return lookupString(name, c.flagSet)
}
func (c *Context) StringSlice(name string) []string {
	return lookupStringSlice(name, c.flagSet)
}
func (c *Context) IntSlice(name string) []int {
	return lookupIntSlice(name, c.flagSet)
}
func (c *Context) Generic(name string) interface{} {
	return lookupGeneric(name, c.flagSet)
}
func (c *Context) GlobalInt(name string) int {
	return lookupInt(name, c.globalSet)
}
func (c *Context) GlobalBool(name string) bool {
	return lookupBool(name, c.globalSet)
}