Rename subtitles files

bash_autocomplete.sh

function _mvsub_complete()
{
    local word=${COMP_WORDS[COMP_CWORD]}
    local filename subname
    if [[ $COMP_CWORD = 1 ]]; then
        # Only allow subtitles files (*.srt)
        COMPREPLY=($(compgen -f -X "!*.srt" -- "${word}"))
    else
        # Only complete non-subtitles files that don't have a matching subtitle
        COMPREPLY=()
        for item in $(compgen -f -X "*.srt" -- "${word}"); do
            filename=$(basename "$item")
            subname="${filename%.*}.srt"
            if [[ ! -e $subname ]]; then
                COMPREPLY+=($item)
            fi
        done
    fi
}

complete -d -F _mvsub_complete mvsub.py

mvsub.py

#!/usr/bin/env python3
import argparse
from os import path, rename as os_rename
import shutil
import sys

def mvsub(subtitles, movie):
    """Return a new path for the subtitles file so that its name is the same
    as the movie file, with only the file extension differing.
    
    If the given subtitles file has no extension, a ValueError is raised.
    
    """
    _, ext = path.splitext(subtitles)
    base, _ = path.splitext(movie)
    
    if not ext:
        raise ValueError("The subtitles file has no extension.")
    
    assert movie != base + ext
    
    return base + ext

def prompt_overwrite(subtitles):
    msg = "The destination file already exists. Overwrite? (Y/N): "
    return input(msg).lower() in {'y', 'yes', '1'}

def get_parser():
    parser = argparse.ArgumentParser(description="Move subtitles files.")
    
    parser.add_argument("subtitles", metavar="SUBS",
                        help="The path to the subtitles file")
    parser.add_argument("movie", metavar="MOVIE",
                        help="The path to the movie file")
    
    parser.add_argument("-c", "--copy", action="store_true",
                        help="Copy the subtitles file instead of moving it.")
    parser.add_argument("-f", "--force", action="store_true",
                        help="Force the overwriting of the destination file if"
                             "it already exists.")
    
    return parser

def main(subtitles, movie, copy=False, force=False):
    try:
        new_subtitles = mvsub(args.subtitles, args.movie)
    except ValueError:
        return "Invalid subtitles file."
    
    if not force and path.exists(new_subtitles):
        if not prompt_overwrite(new_subtitles):
            return
    
    if copy:
        shutil.copy(args.subtitles, new_subtitles)
    else:
        os_rename(args.subtitles, new_subtitles)


if __name__ == '__main__':
    parser = get_parser()
    args = parser.parse_args()
    
    v = main(args.subtitles, args.movie, copy=args.copy, force=args.force)
    sys.exit(v)