add external pager support via ES_JSON_PAGER (#65)

pkg/cfg/config.go

@@ -106,6 +106,8 @@ type Config struct {
 
 	FromNode, ToNode             string // cluster reroute move: -f + -t
 	AllowPrimary, AcceptDataLoss bool   // cluster reroute cancel: -p,-a
+
+	Pager string // api repl: -p || PAGER
 }
 
 func NewConfig() *Config {

pkg/cfg/term.go

@@ -36,3 +36,14 @@ func GetTermWidth() int {
 
 	return 80
 }
+
+func GetTermHeight() int {
+	if term.IsTerminal(int(os.Stdout.Fd())) {
+		_, height, err := term.GetSize(int(os.Stdout.Fd()))
+		if err == nil {
+			return height
+		}
+	}
+
+	return 25
+}