diff --git a/common/lsof/lsof.go b/common/lsof/lsof.go
new file mode 100644
index 0000000..42c06fb
--- /dev/null
+++ b/common/lsof/lsof.go
@@ -0,0 +1,10 @@
+package lsof
+
+import (
+	"errors"
+)
+
+var (
+	ErrNotFound       = errors.New("not found")
+	ErrNotImplemented = errors.New("not implemented")
+)
diff --git a/common/lsof/lsof_other.go b/common/lsof/lsof_other.go
index 2273327..996dae2 100644
--- a/common/lsof/lsof_other.go
+++ b/common/lsof/lsof_other.go
@@ -2,10 +2,6 @@
 
 package lsof
 
-import (
-	"errors"
-)
-
 func GetCommandNameBySocket(network string, addr string, port uint16) (string, error) {
-	return "", errors.New("not implemented")
+	return "", ErrNotImplemented
 }
diff --git a/common/lsof/lsof_unix.go b/common/lsof/lsof_unix.go
index b7e7946..c03c112 100644
--- a/common/lsof/lsof_unix.go
+++ b/common/lsof/lsof_unix.go
@@ -20,7 +20,7 @@ func GetCommandNameBySocket(network string, addr string, port uint16) (string, e
 		// listen on the same udp port. Moreover, if
 		// the application closes the socket immediately
 		// after sending out the packet (e.g. it just
-		// uploading data but not receving any data),
+		// uploading data but not receiving any data),
 		// we may not be able to find it.
 		pattern = fmt.Sprintf("-i%s:%d", network, port)
 	default:
@@ -38,8 +38,8 @@ func GetCommandNameBySocket(network string, addr string, port uint16) (string, e
 		// sockets in the list, just take
 		// the first one for simplicity.
 		if strings.HasPrefix(line, "c") {
-			return line[1:len(line)], nil
+			return line[1:], nil
 		}
 	}
-	return "", errors.New("not found")
+	return "", ErrNotFound
 }
diff --git a/common/lsof/lsof_windows.go b/common/lsof/lsof_windows.go
index 15a080c..88f7520 100644
--- a/common/lsof/lsof_windows.go
+++ b/common/lsof/lsof_windows.go
@@ -3,7 +3,6 @@
 package lsof
 
 import (
-	"errors"
 	"fmt"
 	"syscall"
 	"unsafe"
@@ -24,7 +23,7 @@ func GetCommandNameBySocket(network string, addr string, port uint16) (string, e
 				return getNameByPid(uint32(row.OwningPid))
 			}
 		}
-		return "", errors.New("not found")
+		return "", ErrNotFound
 	case "udp":
 		var udpTable win.MIB_UDPTABLE_OWNER_PID
 		err := getUdpTable(
@@ -56,9 +55,9 @@ func GetCommandNameBySocket(network string, addr string, port uint16) (string, e
 		// 	}
 		// }
 
-		return "", errors.New("not found")
+		return "", ErrNotFound
 	default:
-		return "", errors.New("not found")
+		return "", ErrNotFound
 	}
 }