List missing sequentially numbered files

README.md

for example for photos from a camera (IMG_xxxx.JPG): ./missing-files-in-sequence.sh '*IMG_' 3409 '.jpg'

missing-files-in-sequence.sh

#!/usr/bin/env sh
set -e

prefix=$1
sequence=$2
suffix=$3

item=$sequence
while true ; do
  name="$prefix$item$suffix"
  printf "%s\r" "$name"
  if [ -z "$(find . -name "$name")" ] ; then
    echo "missing: $name"
  fi
  item=$((item + 1))
done