packages/easyscan: fix ordering of merged pages

nix/packages/by-name/easyscan/easyscan.sh

@@ -8,37 +8,44 @@ if [ -e "$OUTPUT_FILE" ]; then
 fi
 
 tempdir="$(mktemp -d)"
+filenames=()
 counter=1
 
 while :; do
 	ok="true"
 	echo "Scanning page $counter"
 
+	CUR_FNAME="$tempdir/easyscan_$counter.pdf"
+
 	# If no size is set, the output will be wonky-sized
 	# 210,297 is the size of A4
-	scanimage -x 210 -y 297 --resolution 300 -o "$tempdir/easyscan_$counter.pdf" >/dev/null 2>&1 ||
+	scanimage -x 210 -y 297 --resolution 300 -o "$CUR_FNAME" >/dev/null 2>&1 ||
 		{
 			echo "Failed to scan page..."
 			ok="false"
 		}
 
+	if $ok; then
+		counter=$((counter += 1))
+		filenames+=("$CUR_FNAME")
+	fi
+
 	IFS= read -r -p "Continue scanning? [Y/n] " cont
 	case "$cont" in
 	[nN])
 		echo "Exiting..."
 		break
 		;;
-	[yY] | *)
-		if $ok; then
-			counter=$((counter += 1))
-		fi
-		;;
+	[yY] | *) ;;
 	esac
 done
 
 # Multiple files are scanned, join them
+#
+# Note: do NOT use the * glob, because bash orders lexicographically and not
+# numerically, the merged ordering will be wrong.
 merged_filename="$tempdir/easyscan_final.pdf"
-pdfunite "$tempdir"/*.pdf "$merged_filename"
+pdfunite "${filenames[@]}" "$merged_filename"
 
 # Copy scan to current directory
 mkdir -p "$(dirname "$OUTPUT_FILE")"