mkv-rm-cover

#!/bin/bash
set -eo pipefail

throw() {
  printf '%s: %s\n' "${0##*/}" "$1" >&2
  return 1
}

if [[ $1 =~ ^(--help|-h)$ ]]; then
  cat >&2 <<'EOF'
Usage: mkv-rm-cover <path...>

Removes all image/jpeg and image/png attachments from the given MKVs.

See also: mkv-clean

Directories are expanded to contained *.mkv files (non-recursive). If no paths
are given, the current directory is used (equivalent to `mkv-rm-cover *.mkv`).
EOF
  exit 1
fi

paths=()
paths_given=
while (( $# > 0 )); do
  if [[ -d "$1" ]]; then
    paths+=("$1"/*.mkv)
    paths_given=1
  else
    paths+=("$1")
    paths_given=1
  fi
  shift
done
if [[ ! $paths_given ]]; then
  paths=(*.mkv)
fi
if (( ${#paths[@]} == 0 )); then
  throw 'no files to process'
fi

for f in "${paths[@]}"; do

  mkvpropedit "$f" \
    --delete-attachment mime-type:image/jpeg \
    --delete-attachment mime-type:image/png |
    grep -v 'Warning: No attachment matched the spec' || true

done