#!/bin/bash
for i in {1..2000}
do
file_name="file_${i}.txt"
if [ ! -f ${file_name} ]
then
echo "${file_name} not exists.."
fi
done
for i in {1..2000};do file_name="file_${i}.txt"; [ -f ${file_name} ] || echo "${file_name} not exists"; done