Fix error message

cli/sslocal/sslocal.go

@@ -53,7 +53,7 @@ func MainCmd() *cobra.Command {
 		Short:   "shadowsocks client as socks5 proxy, sing port",
 		Version: sing.Version,
 		Run: func(cmd *cobra.Command, args []string) {
-			Run(flags)
+			Run(cmd, flags)
 		},
 	}
 
@@ -162,7 +162,7 @@ func NewLocalClient(flags *Flags) (*LocalClient, error) {
 
 	shadowClient, err := shadowsocks.NewClient(dialer, clientConfig)
 	if err != nil {
-		return nil, exceptions.Cause(err, "create shadowsocks")
+		return nil, err
 	}
 
 	client := &LocalClient{
@@ -220,10 +220,12 @@ func (c *LocalClient) NewPacketConnection(conn socks.PacketConn, addr socksaddr.
 	})
 }
 
-func Run(flags *Flags) {
+func Run(cmd *cobra.Command, flags *Flags) {
 	client, err := NewLocalClient(flags)
 	if err != nil {
-		logrus.Fatal(err)
+		logrus.StandardLogger().Log(logrus.FatalLevel, err, "\n\n")
+		cmd.Help()
+		os.Exit(1)
 	}
 	err = client.Start()
 	if err != nil {

protocol/shadowsocks/client.go

@@ -2,7 +2,6 @@ package shadowsocks
 
 import (
 	"context"
-	"github.com/sagernet/sing/protocol/socks"
 	"io"
 	"net"
 	"strconv"
@@ -12,6 +11,7 @@ import (
 	"github.com/sagernet/sing/common/exceptions"
 	"github.com/sagernet/sing/common/rw"
 	"github.com/sagernet/sing/common/socksaddr"
+	"github.com/sagernet/sing/protocol/socks"
 )
 
 var (
@@ -35,6 +35,16 @@ type Client struct {
 }
 
 func NewClient(dialer *net.Dialer, config *ClientConfig) (*Client, error) {
+	if config.Server == "" {
+		return nil, exceptions.New("missing server address")
+	}
+	if config.ServerPort == 0 {
+		return nil, exceptions.New("missing server port")
+	}
+	if config.Method == "" {
+		return nil, exceptions.New("missing server method")
+	}
+
 	cipher, err := CreateCipher(config.Method)
 	if err != nil {
 		return nil, err

protocol/socks/conn.go

@@ -1,11 +1,12 @@
 package socks
 
 import (
+	"net"
+	"time"
+
 	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/buf"
 	"github.com/sagernet/sing/common/socksaddr"
-	"net"
-	"time"
 )
 
 type PacketConn interface {

transport/system/socks.go

@@ -1,13 +1,14 @@
 package system
 
 import (
+	"io"
+	"net"
+	"net/netip"
+
 	"github.com/sagernet/sing/common"
 	"github.com/sagernet/sing/common/exceptions"
 	"github.com/sagernet/sing/common/socksaddr"
 	"github.com/sagernet/sing/protocol/socks"
-	"io"
-	"net"
-	"net/netip"
 )
 
 type SocksHandler interface {