Little refactor on command creation

execext/exec.go

@@ -0,0 +1,22 @@
+package execext
+
+import (
+	"os/exec"
+)
+
+var (
+	// ShPath is path to "sh" command
+	ShPath string
+	// ShExists is true if "sh" command is available on the system
+	ShExists bool
+)
+
+func init() {
+	var err error
+	ShPath, err = exec.LookPath("sh")
+	ShExists = err == nil
+}
+
+func newShCommand(c string) *exec.Cmd {
+	return exec.Command(ShPath, "-c", c)
+}