Quick-'n'-dirty rename of scanned PDFs based on OCR of content (requires Tesseract, ImageMagick)

ocr-rename.sh

#/bin/bash -e
set -o pipefail

REGION_X=1920
REGION_Y=2210
REGION_WIDTH=320
REGION_HEIGHT=100
RENAME_PATTERN='foo-%s.pdf'

for file in "$@"; do
	declare date=$(
		convert -crop "${REGION_WIDTH}x${REGION_HEIGHT}+${REGION_X}+${REGION_Y}" \
			-density 300 -black-threshold 0.3 "$file" png:- |
				tesseract stdin stdout 2>/dev/null |
				grep -oP '\d[\s\d]*/[\d\s]+/[\d\s]+' |
				tr -d ' ' |
				awk -F/ '$3 < 100{$3 += 2000}{print $3 "-" $1 "-" $2}'
	)

	if [ -n "$date" ] && date -d "$date" >/dev/null; then
		rename=$(printf "$RENAME_PATTERN" "$date")

		if [ -e "$rename" ]; then
			echo "Error: $rename would be overwritten; skipping" >&2
		else
			mv -vn "$file" "$rename"
		fi
	else
		echo "Error detecting date of $file; skipping" >&2
	fi
done