How writing a shell script to add enough zeros to have six digits for each number?

Question

I have a list of numbers (each number having less than 6 digits) in a .tsv file like that :
4559
123
etc

and I need to have a list of numbers of 6 digit like that :
004559
000123
etc

Thanks a lot

Answer 1

There's printf in bash that does exactly this -

printf "%0.6d" $value