diff --git a/src/klogd.c b/src/klogd.c
index 18b9f82..410cbd3 100644
--- a/src/klogd.c
+++ b/src/klogd.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * klogd.c - main program for Linux kernel log daemon.
  * Copyright (c) 1995  Dr. G.W. Wettstein <greg@wind.rmcc.com>
  *
diff --git a/src/klogd.h b/src/klogd.h
index 5c00d17..dd82e98 100644
--- a/src/klogd.h
+++ b/src/klogd.h
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * klogd.h - main header file for Linux kernel log daemon.
  * Copyright (c) 1995  Dr. G.W. Wettstein <greg@wind.rmcc.com>
  *
diff --git a/src/ksym.c b/src/ksym.c
index abb34fe..a74465c 100644
--- a/src/ksym.c
+++ b/src/ksym.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * ksym.c - functions for kernel address->symbol translation
  * Copyright (c) 1995, 1996  Dr. G.W. Wettstein <greg@wind.rmcc.com>
  * Copyright (c) 1996 Enjellic Systems Development
diff --git a/src/ksym_mod.c b/src/ksym_mod.c
index e071beb..3807e17 100644
--- a/src/ksym_mod.c
+++ b/src/ksym_mod.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * ksym_mod.c - functions for building symbol lookup tables for klogd
  * Copyright (c) 1995, 1996  Dr. G.W. Wettstein <greg@wind.rmcc.com>
  * Copyright (c) 1996 Enjellic Systems Development
diff --git a/src/ksyms.h b/src/ksyms.h
index 0ee3c3e..c279c72 100644
--- a/src/ksyms.h
+++ b/src/ksyms.h
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * ksym.h - Definitions for symbol table utilities.
  * Copyright (c) 1995, 1996  Dr. G.W. Wettstein <greg@wind.rmcc.com>
  * Copyright (c) 1996 Enjellic Systems Development
diff --git a/src/module.h b/src/module.h
index e4ac367..5d5f1cc 100644
--- a/src/module.h
+++ b/src/module.h
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * module.h - Miscellaneous module definitions
  * Copyright (c) 1996 Richard Henderson <rth@tamu.edu>
  * Copyright (c) 2004-7 Martin Schulze <joey@infodrom.org>
diff --git a/src/oops.c b/src/oops.c
index 67f0ad0..8060ad5 100644
--- a/src/oops.c
+++ b/src/oops.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * oops.c - Dummy loadable module for testing klogd.
  * Copyright (c) 2007  Martin Schulze <joey@infodrom.org>
  *
diff --git a/src/pidfile.c b/src/pidfile.c
index 4fb30be..831ab90 100644
--- a/src/pidfile.c
+++ b/src/pidfile.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * pidfile.c - interact with pidfiles
  * Copyright (c) 1995  Martin Schulze <Martin.Schulze@Linux.DE>
  *
diff --git a/src/pidfile.h b/src/pidfile.h
index b782637..5bd9cf4 100644
--- a/src/pidfile.h
+++ b/src/pidfile.h
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
  * pidfile.h - interact with pidfiles
  * Copyright (c) 1995  Martin Schulze <Martin.Schulze@Linux.DE>
  *
diff --git a/src/syslog.c b/src/syslog.c
index 4d49717..5db3e97 100644
--- a/src/syslog.c
+++ b/src/syslog.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1983, 1988, 1993
  *	The Regents of the University of California.  All rights reserved.
  *
diff --git a/src/syslogd.c b/src/syslogd.c
index b0d958d..3e30b58 100644
--- a/src/syslogd.c
+++ b/src/syslogd.c
@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
  * Copyright (c) 1983, 1988, 1993
  *	The Regents of the University of California.  All rights reserved.
  *