diff --git a/rebuild_db.py b/rebuild_db.py
index 17f193e..ca0bc8f 100755
--- a/rebuild_db.py
+++ b/rebuild_db.py
@@ -13,10 +13,6 @@
 # along with this program; if not, write to the Free Software
 # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 
-from builtins import input
-from builtins import map
-from builtins import range
-from functools import reduce
 
 __title__ = "KeyJ's iPod shuffle Database Builder"
 __version__ = "1.0"
@@ -67,6 +63,7 @@ __email__ = "martin.fiedler@gmx.net"
 """
 
 import functools, sys, os, os.path, array, random, fnmatch, operator, string
+from builtins import map, input, range
 from io import BytesIO
 from typing import TextIO
 
@@ -149,14 +146,14 @@ def ParseRule(rule):
     sep_pos = min([rule.find(sep) for sep in "~=<>" if rule.find(sep) > 0])
     prop = rule[:sep_pos].strip()
     if not prop in KnownProps:
-        log("WARNING: unknown property `%s'" % prop)
+        log(f"WARNING: unknown property '{prop}'")
     return prop, rule[sep_pos], ParseValue(rule[sep_pos + 1:].strip())
 
 
 def ParseAction(action):
     prop, value = list(map(str.strip, action.split('=', 1)))
     if not prop in KnownProps:
-        log("WARNING: unknown property `%s'" % prop)
+        log(f"WARNING: unknown property '{prop}'")
     return prop, ParseValue(value)
 
 
@@ -174,7 +171,7 @@ def ParseRuleLine(line):
         else:
             return list(map(ParseRule, ruleset)), actions
     except OSError:  # (ValueError,IndexError,KeyError):
-        log("WARNING: rule `%s' is malformed, ignoring" % line)
+        log(f"WARNING: rule '{line}' is malformed, ignoring")
         return None
 
 
@@ -191,14 +188,14 @@ def rename_safely(path, name):
     newname = ''.join(map(safe_char, base))
     if name == newname + ext:
         return name
-    if os.path.exists("%s/%s%s" % (path, newname, ext)):
+    if os.path.exists(f"{path}/{newname}{ext}"):
         i = 0
-        while os.path.exists("%s/%s_%d%s" % (path, newname, i, ext)):
+        while os.path.exists(f"{path}/{newname}_{i}{ext}"):
             i += 1
-        newname += "_%d" % i
+        newname += f"_{i}"
     newname += ext
     try:
-        os.rename("%s/%s" % (path, name), "%s/%s" % (path, newname))
+        os.rename(f"{path}/{name}", f"{path}/{newname}")
     except OSError:
         pass  # don't fail if the rename didn't work
     return newname
@@ -220,7 +217,7 @@ def write_to_db(filename):
 
     # check and apply rules
     for ruleset, action in Rules:
-        if reduce(operator.__and__, [MatchRule(props, rule) for rule in ruleset], True):
+        if functools.reduce(operator.__and__, [MatchRule(props, rule) for rule in ruleset], True):
             props.update(action)
     if props['ignore']: return 0
 
@@ -269,7 +266,7 @@ def cmp(a, b):
 
 def file_entry(path, name, prefix=""):
     if not name or name[0] == ".": return None
-    fullname = "%s/%s" % (path, name)
+    fullname = f"{path}/{name}"
     may_rename = not (fullname.startswith("./iPod_Control")) and args.rename
     try:
         if os.path.islink(fullname):
@@ -293,7 +290,7 @@ def browse(path: string, interactive: bool):
     if not displaypath: displaypath = "/"
 
     while interactive:
-        choice = input("include `%s'? [(Y)es, (N)o, (A)ll] " % displaypath)[:1].lower()
+        choice = input(f"include '{displaypath}'? [(Y)es, (N)o, (A)ll] ")[:1].lower()
         if not choice: continue
 
         # all/alle/tous/<dontknow>
@@ -310,7 +307,7 @@ def browse(path: string, interactive: bool):
         subdirs = [x[2] for x in files if not x[0]]
         files = [x for x in files if x[0]]
         for dir in subdirs:
-            subpath = "%s/%s" % (path, dir)
+            subpath = f"{path}/{dir}"
             try:
                 files.extend([x for x in [
                     file_entry(subpath, name, dir + "/") for name in os.listdir(subpath)
@@ -323,13 +320,13 @@ def browse(path: string, interactive: bool):
 
     real_count = 0
     for item in files:
-        fullname = "%s/%s" % (path, item[2])
+        fullname = f"{path}/{item[2]}"
         if item[0]:
             real_count += write_to_db(fullname[1:])
         else:
             browse(fullname, interactive)
 
-    log("%s: %d files (out of %d)" % (displaypath, real_count, count))
+    log(f"{displaypath}: {real_count} files (out of {count})")
 
 
 ################################################################################
@@ -489,7 +486,7 @@ Please make sure that:
 
     if len(header) == 51:
         log("Using iTunesSD headers from existing database.")
-        if KnownEntries: log("Collected %d entries from existing database." % len(KnownEntries))
+        if KnownEntries: log(f"Collected {len(KnownEntries)} entries from existing database.")
     else:
         del header[18:]
         if len(header) == 18: log("Using iTunesSD main header from existing database.")
@@ -516,7 +513,7 @@ Please make sure that:
     try:
         for dir in dirs:
             browse("./" + dir, args.interactive)
-        log("%d playable files were found on your iPod." % total_count)
+        log(f"{total_count} playable files were found on your iPod.")
         log()
         log("Fixing iTunesSD header.")
         iTunesSD_file.seek(0)