diff --git a/files/rsync-backup b/files/rsync-backup
index 76c7a74..f7e553f 100755
--- a/files/rsync-backup
+++ b/files/rsync-backup
@@ -5,30 +5,40 @@ import subprocess
 import os
 import sys
 import shlex
+import json
 from argparse import ArgumentParser
 
-VERSION = "1.1"
+VERSION = "1.2"
 
 
 class RSB:
     def __init__(self, options):
+        self.options = options
+        self.lock = options.lock
         self.base_folder = options.base_folder
         self.backup_source = options.backup_source
         self.rsync_args = options.rsync_args
         self.delete_older = options.del_older
         self.keep_n = options.keep_n
         self.delete_disk_percentage = options.del_used
+        self.config_file = os.path.join(self.base_folder, "rsync-backup.txt")
+        self.lock_file = os.path.join(self.base_folder, "rsync-backup.lock")
 
         if not self.backup_source.endswith("/"):
             self.backup_source += "/"
         self.current = os.path.join(self.base_folder, "current")
         self.folder_format = "backup-%Y%m%d-%H%M%S"
         os.makedirs(self.current, exist_ok=True)
+
+        self.lock_check()
+        self.write_config()
         self.clean_old()
         success = self.make_backup()
         if success:
             self.make_hardlinks()
-        else:
+
+        self.lock_clean()
+        if not success:
             print("Program exited with errors")
             sys.exit(1)
 
@@ -107,6 +117,46 @@ class RSB:
         success = exitcode in (0, 23, 24, 25)
         return success
 
+    def write_config(self):
+
+        conf = json.dumps(vars(self.options))
+        with open(self.config_file, "wt") as fp:
+            fp.write(
+                """# RSync Backup version {version}
+# {conf}
+rsync-backup \\
+    --del-older {older} \\
+    --keep-number {number} \\
+    --del-disk-used {used} \\
+    --rsync-args '{args}' \\
+    {source} \\
+    {base}
+""".format(
+                    conf=conf,
+                    version=VERSION,
+                    older=self.delete_older,
+                    number=self.keep_n,
+                    used=self.delete_disk_percentage,
+                    args=self.rsync_args,
+                    source=self.backup_source,
+                    base=self.base_folder,
+                )
+            )
+
+    def lock_check(self):
+        if self.options.lock:
+            if os.path.exists(self.lock_file):
+                raise FileExistsError("Lock file '{}' exists".format(self.lock_file))
+            with open(self.lock_file, "wt") as fp:
+                fp.write(str(os.getpid()))
+
+    def lock_clean(self):
+        if self.options.lock:
+            try:
+                os.remove(self.lock_file)
+            except FileNotFoundError:
+                pass
+
 
 def get_opts():
 
@@ -145,6 +195,13 @@ def get_opts():
         default="-aP --del",
         help="Rsync arguments. Add excludes here (example  '-vxP --exclude folder/'). Defaults: '%(default)s'",
     )
+    parser.add_argument(
+        "--lock",
+        dest="lock",
+        action="store_true",
+        default=False,
+        help="Use locking to prevent concurrent backups",
+    )
     parser.add_argument("--version", action="version", version=VERSION)
     parser.add_argument(
         "backup_source", action="store", help="Source URL to backup with rsync"