rename_srt.bat

@echo off
setlocal enabledelayedexpansion

echo It require a few steps, preparation:
echo 1. extract .SRT from .MKV files, where episode number is on line in format like: [Episode 27]
echo 2. rename .SRT files as .MKV videos
echo 3. run this .BAT file

:: Iterate through all .srt files in the current directory
for %%f in (*.srt) do (
    set "episode_number="

    :: Extract the line containing '[episode N]' and parse the episode number
    for /f "tokens=2 delims=[] " %%a in ('findstr /i /c:"[episode" "%%f"') do (
        set "episode_number=%%a"
    )

    :: Check if an episode number was found
    if defined episode_number (
        :: Construct the new base filename for both SRT and MKV files
        set "base_filename=episode_!episode_number!"

        :: Rename the SRT file
        ren "%%f" "!base_filename!.srt"
        echo Renamed SRT file: %%f to !base_filename!.srt

        :: Construct the corresponding MKV filename
        :: set "mkvname=!base_filename!.mkv"
        set "mkvname=%%f"
        set "mkvname=!mkvname:.srt=.mkv!"

        :: Check if the MKV file exists before renaming
        if exist "!mkvname!" (
            :: Rename the MKV file
            ren "!mkvname!" "!base_filename!.mkv"
            echo Renamed MKV file: !mkvname! to !base_filename!.mkv!
        ) else (
            echo WARNING: Corresponding MKV file !mkvname! not found for %%f
        )
    ) else (
        echo WARNING: No episode number found in file %%f
    )
)

endlocal