Bash fix filenames order (common linux file misordering)

#!/bin/bash
# This scripts helps you to fix file ordering linux issues.
# They are related to the idea that images without leading zeros (frame1.png but not frame0001.png)
# is incorrectly ordered by the system and, thus, cannot be used in ffmpeg or wherever other scripts,
# in a correct order. So, this scripts adds leading zeros. In this example, in scans file from 1 to 2500.

m1=($(seq 1 2500))
m2=($(seq -w 0001 2500))

echo ${m1[20]}
echo ${m2[20]}

for i in {1..2500..1}; do
mv frame${m1[$i]}.png frame${m2[$i]}.png
done