BASH Question: Incrementing 2 variables to produce a file that looks like 200001.txt, 200002.txt, etc

Question

I got the first section to create the years, but getting the months and incrementing them is stumping me.

#!/bin/bash
varRan=$(( $RANDOM ))
newdir="testing_"$varRan
#echo  $newdir

mkdir $newdir
cd ~/$newdir
for   ((i = 2000; i<= 2022 ; i++; )); do
        for  ((m = 1; m<= 12 ; m++; )) do
        touch $i$m".txt"
done
#       touch $i$m".txt"
done

Answer 1

Using a shell expansion with a leading zero does what you need.

#/bin/bash

newdir="testing_$RANDOM"

mkdir "${newdir}"; cd "${newdir}"

for y in {2000..2022}; do
    for m in {01..12}; do
        touch "prefix_$y$m.txt"
    done
done

Answer 2

You can use date for generating dates in shell with custom format

$ date +%Y-%m-%d -d "2002-03-28 +1 days" 
2002-03-29

$ date +%Y-%m-%d -d "2002-03-28 +1 months"
2002-04-28

$ date +%Y-%m-%d -d "2002-03-28 +1 years" 
2003-03-28