How the `--force` Option Overrides Existing File Checks in you-get

The --force (-f) flag in you-get bypasses file existence checks by setting the global force variable to True, which causes url_save() in src/you_get/common.py to open files in write-binary mode ('wb') instead of append mode, overwriting any existing content without prompting.

When downloading media with the you-get command-line tool, the utility normally protects existing files by skipping downloads or prompting for confirmation. The --force option disables these safeguards entirely, allowing seamless automation and re-downloads. This behavior is implemented across the argument parser and the core download routine in the src/you_get/common.py module.

Argument Parsing and Global Flag

CLI Definition in common.py

The flag originates in the argument parser defined in src/you_get/common.py. The download_grp argument group registers the option as a boolean flag:

download_grp.add_argument('-f', '--force', action='store_true', default=False,
                         help='Force overwriting existing files')

When a user invokes you-get -f, argparse stores True in the resulting namespace.

Global Variable Assignment

After parser.parse_args() executes, the script_main function (around lines 1708–1709) copies this value into the module-wide variable force:

global force
force = args.force

This global variable acts as the source of truth for all subsequent file operations during the session.

File Existence Logic in url_save()

The Conditional Check

The core download logic resides in url_save(), also located in src/you_get/common.py. The function first checks whether the target file already exists:

if os.path.exists(filepath):
    if not force and (file_size == os.path.getsize(filepath) or
                      skip_existing_file_size_check):
        # ... skip or prompt logic

When force is False, the downloader will:

• Skip the download if the existing file matches the expected size (or if --skip-existing-file-size-check is active).
• Prompt the user to overwrite, or automatically rename the file if auto_rename is enabled.

When force is True, the if not force condition evaluates to False, bypassing the entire skip/prompt block. The downloader proceeds directly to the overwrite path without checking file sizes or user preferences.

Open Mode Selection

Later in the same function, the write mode is determined by the force flag:

if not force:
    open_mode = 'ab'          # append to a partially-downloaded file

else:
    open_mode = 'wb'          # truncate and start fresh

With --force enabled, the file opens in write-binary mode ('wb'). This truncates any existing file contents and writes the new data stream from byte zero, effectively replacing the old file regardless of its previous state.

Practical Usage Examples

Normal operation respects existing files and avoids accidental data loss:

# Default behavior: skips or asks before overwriting

you-get https://example.com/video.mp4

Enabling the override forces immediate replacement:

# Force overwrite: replaces video.mp4 without confirmation

you-get --force https://example.com/video.mp4

# Short form equivalent

you-get -f https://example.com/video.mp4

Interaction with Other Flags

The --force flag takes precedence over --auto-rename. When both flags are present, the force logic executes first, opening the file in 'wb' mode and overwriting the existing target. The auto-rename logic only triggers when force is False and a naming collision occurs.

Summary

• Argument definition: The -f/--force flag is defined in src/you_get/common.py as a store_true action with a default of False.
• Global state: script_main assigns the parsed value to the module-level force variable (lines 1708–1709).
• Existence bypass: In url_save(), the if not force guard prevents size comparisons and user prompts when enabled.
• Overwrite mechanism: The flag switches the file open mode from append ('ab') to write-binary ('wb'), truncating existing files.
• Precedence: --force overrides --auto-rename and --skip-existing-file-size-check, ensuring unconditional replacement.

Frequently Asked Questions

What happens when I use --force with --auto-rename?

The --force flag takes priority. According to the logic in src/you_get/common.py, the downloader checks force before evaluating auto_rename. When force is True, the file opens in 'wb' mode immediately, overwriting any existing file with the same name. The auto-rename logic only executes when force is False and a collision is detected.

Does --force check file sizes before overwriting?

No. When --force is enabled, the downloader bypasses the size comparison logic entirely. Normally, url_save() compares file_size against os.path.getsize(filepath) to detect incomplete downloads, but the if not force condition prevents this check from executing, forcing a full re-download regardless of existing file size.

Which source file controls the overwrite behavior?

The overwrite behavior is implemented in src/you_get/common.py. This file contains both the CLI argument definition for -f/--force and the url_save() function that consumes the global force variable to determine whether to append to or replace existing files.

Is there a short form for --force?

Yes. The argument parser defines -f as the short alias for --force. Both you-get -f <URL> and you-get --force <URL> produce identical behavior, triggering the unconditional overwrite mechanism described in the url_save() implementation.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}