# Bulk Rename Files from the Command Line with Python

> Source: <https://dev.to/nportercodes/bulk-rename-files-from-the-command-line-with-python-3ld8>
> Published: 2026-05-24 04:54:07+00:00

# Bulk Rename Files from the Command Line with Python

Renaming hundreds of files manually is tedious. Here is how to do it with a simple Python script.

## The Problem

You have a folder full of photos and you need to add prefixes, change extensions, or convert case.

## Quick Solution

``` python
import os, sys

def rename_files(directory, prefix=""):
    for f in os.listdir(directory):
        fp = os.path.join(directory, f)
        if not os.path.isfile(fp): continue
        name, ext = os.path.splitext(f)
        new_path = os.path.join(directory, prefix + name + ext)
        print(f"{f} -> {os.path.basename(new_path)}")

if __name__ == "__main__":
    rename_files(sys.argv[1], sys.argv[2] if len(sys.argv) > 2 else "")
python renamer.py ./photos vacation_
```

This adds a prefix to every file in the directory.

## Advanced Features

The full CLI tool (Bulk Renamer Pro) adds:

- Regex find-and-replace
- Case conversion
- Auto-numbering
- Extension filtering
- Recursive scanning
- Safe dry-run mode

## Why CLI?

- Fast: one command, hundreds of files
- Repeatable: same result every time
- Scriptable: chain with other commands

Built with Python 3. No external dependencies.