diff --git a/basefn/extfunc.go b/basefn/extfunc.go
index fde7dbc56..31efac180 100644
--- a/basefn/extfunc.go
+++ b/basefn/extfunc.go
@@ -2,7 +2,7 @@ package basefn
 
 import "fmt"
 
-// DataSize format bytes number friendly.
+// DataSize format bytes number friendly. eg: 1024 => 1KB, 1024*1024 => 1MB
 //
 // Usage:
 //
diff --git a/mathutil/number.go b/mathutil/number.go
index 64e9be873..5b1359463 100644
--- a/mathutil/number.go
+++ b/mathutil/number.go
@@ -25,7 +25,8 @@ func ElapsedTime(startTime time.Time) string {
 	return fmt.Sprintf("%.3f", time.Since(startTime).Seconds()*1000)
 }
 
-// DataSize format value. alias format.DataSize()
+// DataSize format value to data size string. eg: 1024 => 1KB, 1024*1024 => 1MB
+// alias format.DataSize()
 func DataSize(size uint64) string {
 	return basefn.DataSize(size)
 }
diff --git a/sysutil/cmdr/cmd.go b/sysutil/cmdr/cmd.go
index 8ebda4415..f91a41184 100644
--- a/sysutil/cmdr/cmd.go
+++ b/sysutil/cmdr/cmd.go
@@ -21,6 +21,8 @@ type Cmd struct {
 	Name string
 	// DryRun if True, not real execute command
 	DryRun bool
+	// Vars mapping
+	Vars map[string]string
 
 	// BeforeRun hook
 	BeforeRun func(c *Cmd)
@@ -28,11 +30,6 @@ type Cmd struct {
 	AfterRun func(c *Cmd, err error)
 }
 
-// WrapGoCmd instance
-func WrapGoCmd(cmd *exec.Cmd) *Cmd {
-	return &Cmd{Cmd: cmd}
-}
-
 // NewGitCmd instance
 func NewGitCmd(subCmd string, args ...string) *Cmd {
 	return NewCmd("git", subCmd).AddArgs(args)
@@ -43,7 +40,6 @@ func NewGitCmd(subCmd string, args ...string) *Cmd {
 // see exec.Command
 func NewCmdline(line string) *Cmd {
 	bin, args := cmdline.NewParser(line).WithParseEnv().BinAndArgs()
-
 	return NewCmd(bin, args...)
 }
 
@@ -51,17 +47,21 @@ func NewCmdline(line string) *Cmd {
 //
 // see exec.Command
 func NewCmd(bin string, args ...string) *Cmd {
-	return &Cmd{
-		Cmd: exec.Command(bin, args...),
-	}
+	return WrapGoCmd(exec.Command(bin, args...))
 }
 
 // CmdWithCtx create new instance with context.
 //
 // see exec.CommandContext
 func CmdWithCtx(ctx context.Context, bin string, args ...string) *Cmd {
+	return WrapGoCmd(exec.CommandContext(ctx, bin, args...))
+}
+
+// WrapGoCmd instance
+func WrapGoCmd(cmd *exec.Cmd) *Cmd {
 	return &Cmd{
-		Cmd: exec.CommandContext(ctx, bin, args...),
+		Cmd:  cmd,
+		Vars: make(map[string]string),
 	}
 }
 
@@ -260,6 +260,20 @@ func (c *Cmd) WithArgsIf(args []string, exprOk bool) *Cmd {
 	return c
 }
 
+// WithVars add vars and returns the current object
+func (c *Cmd) WithVars(vs map[string]string) *Cmd {
+	if len(vs) > 0 {
+		c.Vars = vs
+	}
+	return c
+}
+
+// SetVar add var and returns the current object
+func (c *Cmd) SetVar(name, val string) *Cmd {
+	c.Vars[name] = val
+	return c
+}
+
 // -------------------------------------------------
 // helper command
 // -------------------------------------------------