inplace.py

#!/usr/bin/env python3
import argparse, pathlib, shutil, subprocess, tempfile


def run_substituted_cmd(
    cmd: list[str], file: pathlib.Path, placeholder: str
) -> bytes:
    cmd = (
        [str(file) if arg == placeholder else arg for arg in cmd]
        if placeholder in cmd
        else cmd + [str(file)]
    )

    return subprocess.run(cmd, capture_output=True, check=True).stdout


def replace_file(file: pathlib.Path, contents: bytes):
    with tempfile.NamedTemporaryFile() as tmp:
        tmp.write(contents)
        tmp.flush()
        shutil.copy(tmp.name, file)


def main():
    parser = argparse.ArgumentParser(
        description="Run any command on a list of files and overwrite them with the output."
    )
    parser.add_argument(
        "-p",
        "--placeholder",
        default="%",
        help="Placeholder for the file name (default: %)",
    )
    parser.add_argument(
        "-f",
        "--files",
        type=pathlib.Path,
        nargs="+",
        required=True,
        help="Files to edit (required)",
    )
    parser.add_argument("cmd", nargs="+")

    opts = parser.parse_args()
    for file in opts.files:
        output = run_substituted_cmd(opts.cmd, file, opts.placeholder)
        replace_file(file, output)


if __name__ == "__main__":
    main()