diff --git a/LICENSE b/LICENSE
new file mode 100644
index 0000000..bde8f41
--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) [year] [fullname]
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/renamebycsv/renamebycsv.py b/renamebycsv/renamebycsv.py
new file mode 100755
index 0000000..42c2cb9
--- /dev/null
+++ b/renamebycsv/renamebycsv.py
@@ -0,0 +1,133 @@
+#!/usr/bin/env python3
+
+import argparse
+import csv
+import os
+import re
+from typing import Iterable
+import logging
+
+
+def find_all_candidates(input_dir: str, regex: str, recursive: bool):
+    results = []
+    for subitem in os.listdir(input_dir):
+        subitem_path = os.path.join(input_dir, subitem)
+        match = re.match(regex, subitem)
+        if os.path.isdir(subitem_path) and recursive:
+            logging.debug(f'Checking directory "{subitem}"...')
+            results.extend(find_all_candidates(subitem_path, regex, recursive))
+        else:
+            if not match:
+                logging.debug(f'Ignoring "{subitem}"...')
+                continue
+            results.append((subitem_path, subitem, match))
+            logging.debug(f'Collecting "{subitem}"...')
+    return results
+
+
+def rename(
+    csv_path: str,
+    candidates: Iterable[tuple[str, str, re.Match]],
+    current: str,
+    become: str,
+    dry: bool,
+):
+    replacement_dict = {}
+    with open(csv_path, "r") as csv_fd:
+        reader = csv.reader(csv_fd)
+        current_col_ind = None
+        become_col_ind = None
+        for row in reader:
+            if current_col_ind is None and become_col_ind is None:
+                current_col_ind = row.index(current)
+                become_col_ind = row.index(become)
+                continue
+            if (
+                row[current_col_ind] in replacement_dict
+                and replacement_dict[row[current_col_ind]] != row[become_col_ind]
+            ):
+                raise Exception("Duplicate current key.")
+            replacement_dict[row[current_col_ind]] = row[become_col_ind]
+    for subitem_path, subitem, match in candidates:
+        original = subitem_path
+        objective = os.path.join(
+            os.path.dirname(subitem_path),
+            re.sub(match.re, replacement_dict[match.group(1)], subitem),
+        )
+        logging.info(f'Will rename "{original}" to "{os.path.basename(objective)}"')
+        if os.path.exists(objective):
+            logging.error(
+                f'Path at "{objective}" exists, not continuing. '
+                "Use -f to overwrite instead of stopping."
+            )
+            exit(1)
+        if not dry:
+            os.rename(original, objective)
+    if dry:
+        logging.info("No file names were modified.")
+
+
+def main():
+    program_name = "renamebycsv"
+    argparser = argparse.ArgumentParser(
+        program_name, "Rename all files by using a CSV as a dictionary."
+    )
+    argparser.add_argument(
+        "input_dir",
+        help="The directory containing the items that is to be renamed.",
+        metavar="I",
+    )
+    argparser.add_argument(
+        "regex",
+        help="The regex to apply to each file name. The first capture group is used to "
+        "perform the replacement.",
+        metavar="R",
+    )
+    argparser.add_argument(
+        "csv",
+        help="The CSV to use as the dictionary for the substitutions in file name.",
+        metavar="C",
+    )
+    argparser.add_argument(
+        "current",
+        help="The column header to look for the text matched by the regex.",
+        metavar="F",
+    )
+    argparser.add_argument(
+        "become", help="The column header to replace the regex match.", metavar="T"
+    )
+    argparser.add_argument(
+        "-r",
+        "--recursive",
+        help="Perform renaming action recursively",
+        action="store_true",
+    )
+    argparser.add_argument(
+        "-f",
+        "--force",
+        help="Overwrite files if file already exists",
+        action="store_true",
+    )
+    argparser.add_argument(
+        "-d", "--dry", help="Do not perform any renames", action="store_true"
+    )
+    argparser.add_argument(
+        "-V",
+        "--verbosity",
+        help="Set the logging verbosity",
+        required=False,
+        type=str,
+        default="INFO",
+    )
+
+    args = argparser.parse_args()
+    logging.basicConfig(
+        format="[%(filename)s %(asctime)s - %(levelname)s] %(message)s",
+        level=args.verbosity.upper(),
+    )
+    candidates = find_all_candidates(args.input_dir, args.regex, args.recursive)
+    rename(args.csv, candidates, args.current, args.become, args.dry)
+
+
+if __name__ == "__main__":
+    main()