diff --git a/errors/gerror/gerror.go b/errors/gerror/gerror.go
index ac11e323d..282dcb40a 100644
--- a/errors/gerror/gerror.go
+++ b/errors/gerror/gerror.go
@@ -241,22 +241,30 @@ func WrapCodeSkipf(code gcode.Code, skip int, err error, format string, args ...
 }
 
 // Code returns the error code of current error.
-// It returns CodeNil if it has no error code or it does not implements interface Code.
+// It returns CodeNil if it has no error code neither it does not implement interface Code.
 func Code(err error) gcode.Code {
-	if err != nil {
-		if e, ok := err.(iCode); ok {
-			return e.Code()
-		}
+	if err == nil {
+		return gcode.CodeNil
+	}
+	if e, ok := err.(iCode); ok {
+		return e.Code()
+	}
+	if e, ok := err.(iNext); ok {
+		return Code(e.Next())
 	}
 	return gcode.CodeNil
 }
 
 // Cause returns the root cause error of `err`.
 func Cause(err error) error {
-	if err != nil {
-		if e, ok := err.(iCause); ok {
-			return e.Cause()
-		}
+	if err == nil {
+		return nil
+	}
+	if e, ok := err.(iCause); ok {
+		return e.Cause()
+	}
+	if e, ok := err.(iNext); ok {
+		return Cause(e.Next())
 	}
 	return err
 }
diff --git a/errors/gerror/gerror_error.go b/errors/gerror/gerror_error.go
index c69f01836..e3491b7bf 100644
--- a/errors/gerror/gerror_error.go
+++ b/errors/gerror/gerror_error.go
@@ -65,6 +65,9 @@ func (err *Error) Code() gcode.Code {
 	if err == nil {
 		return gcode.CodeNil
 	}
+	if err.code == gcode.CodeNil {
+		return Code(err.Next())
+	}
 	return err.code
 }
 
diff --git a/os/gcfg/gcfg.go b/os/gcfg/gcfg.go
index 0e080afab..5342f56e3 100644
--- a/os/gcfg/gcfg.go
+++ b/os/gcfg/gcfg.go
@@ -13,6 +13,8 @@ import (
 
 	"github.com/gogf/gf/v2/container/gmap"
 	"github.com/gogf/gf/v2/container/gvar"
+	"github.com/gogf/gf/v2/errors/gcode"
+	"github.com/gogf/gf/v2/errors/gerror"
 	"github.com/gogf/gf/v2/internal/command"
 	"github.com/gogf/gf/v2/internal/intlog"
 	"github.com/gogf/gf/v2/internal/utils"
@@ -140,7 +142,7 @@ func (c *Config) Get(ctx context.Context, pattern string, def ...interface{}) (*
 // Fetching Rules: Environment arguments are in uppercase format, eg: GF_PACKAGE_VARIABLE.
 func (c *Config) GetWithEnv(ctx context.Context, pattern string, def ...interface{}) (*gvar.Var, error) {
 	value, err := c.Get(ctx, pattern)
-	if err != nil {
+	if err != nil && gerror.Code(err) != gcode.CodeNotFound {
 		return nil, err
 	}
 	if value == nil {
@@ -162,7 +164,7 @@ func (c *Config) GetWithEnv(ctx context.Context, pattern string, def ...interfac
 // Fetching Rules: Command line arguments are in lowercase format, eg: gf.package.variable.
 func (c *Config) GetWithCmd(ctx context.Context, pattern string, def ...interface{}) (*gvar.Var, error) {
 	value, err := c.Get(ctx, pattern)
-	if err != nil {
+	if err != nil && gerror.Code(err) != gcode.CodeNotFound {
 		return nil, err
 	}
 	if value == nil {
diff --git a/os/gcfg/gcfg_adapter_file_path.go b/os/gcfg/gcfg_adapter_file_path.go
index fa65ecca5..b23c682fc 100644
--- a/os/gcfg/gcfg_adapter_file_path.go
+++ b/os/gcfg/gcfg_adapter_file_path.go
@@ -219,7 +219,7 @@ func (c *AdapterFile) GetFilePath(fileName ...string) (path string, err error) {
 		} else {
 			buffer.WriteString(fmt.Sprintf(`cannot find config file "%s" with no path configured`, usedFileName))
 		}
-		err = gerror.New(buffer.String())
+		err = gerror.NewCode(gcode.CodeNotFound, buffer.String())
 	}
 	return
 }
diff --git a/os/gcfg/gcfg_z_example_test.go b/os/gcfg/gcfg_z_example_test.go
new file mode 100644
index 000000000..a64a2e4ca
--- /dev/null
+++ b/os/gcfg/gcfg_z_example_test.go
@@ -0,0 +1,66 @@
+// Copyright GoFrame Author(https://goframe.org). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+package gcfg_test
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/gogf/gf/v2/frame/g"
+	"github.com/gogf/gf/v2/os/gcmd"
+	"github.com/gogf/gf/v2/os/gctx"
+	"github.com/gogf/gf/v2/os/genv"
+)
+
+func ExampleConfig_GetWithEnv() {
+	var (
+		key = `ENV_TEST`
+		ctx = gctx.New()
+	)
+	v, err := g.Cfg().GetWithEnv(ctx, key)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("env:%s\n", v)
+	if err = genv.Set(key, "gf"); err != nil {
+		panic(err)
+	}
+	v, err = g.Cfg().GetWithEnv(ctx, key)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("env:%s", v)
+
+	// Output:
+	// env:
+	// env:gf
+}
+
+func ExampleConfig_GetWithCmd() {
+	var (
+		key = `cmd.test`
+		ctx = gctx.New()
+	)
+	v, err := g.Cfg().GetWithCmd(ctx, key)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("cmd:%s\n", v)
+	// Re-Initialize custom command arguments.
+	os.Args = append(os.Args, fmt.Sprintf(`--%s=yes`, key))
+	gcmd.Init(os.Args...)
+	// Retrieve the configuration and command option again.
+	v, err = g.Cfg().GetWithCmd(ctx, key)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("cmd:%s", v)
+
+	// Output:
+	// cmd:
+	// cmd:yes
+}