Batch file processing: extract .rar and convert MKV in bulk

When you have a folder full of files to process, a bash loop handles it without needing to open any GUI.

Extract all .rar files from a directory

for f in *.rar; do unrar e "$f"; done

unrar e extracts files without preserving the directory structure (everything goes to the current folder). If you want to preserve the folder structure, use unrar x instead of unrar e.

If the .rar files are parts of a single archive (.part1.rar, .part2.rar, etc.), just run it on the first one:

unrar e arquivo.part1.rar

unrar finds the other parts automatically.

Convert all .mkv to .mp4

for f in *.mkv; do ffmpeg -hide_banner -i "$f" -c:v libx264 -c:a copy "$f.mp4"; done

• -hide_banner → suppresses ffmpeg’s long header
• -c:v libx264 → re-encodes video in H.264 (compatible with virtually everything)
• -c:a copy → copies audio without re-encoding (faster and lossless)
• "$f.mp4" → the output name will be video.mkv.mp4 — if you want video.mp4, use "${f%.mkv}.mp4"

Version with clean naming:

for f in *.mkv; do ffmpeg -hide_banner -i "$f" -c:v libx264 -c:a copy "${f%.mkv}.mp4"; done

Performance considerations

Video conversion is CPU-intensive. If you have an NVIDIA GPU and ffmpeg compiled with NVENC support, you can speed things up significantly:

ffmpeg -i "$f" -c:v h264_nvenc -c:a copy "${f%.mkv}.mp4"

For Intel with Quick Sync:

ffmpeg -i "$f" -c:v h264_qsv -c:a copy "${f%.mkv}.mp4"

But for general use, libx264 with -preset fast is already a good balance:

ffmpeg -i "$f" -c:v libx264 -preset fast -c:a copy "${f%.mkv}.mp4"