How to zero-pad numeric variables in zsh (and maybe also bash?)

Question

In zsh, when I have to create a bunch of files with zsh, I usually do something like:

for x in $(seq 1 1000); do .....; done 

This works fine, it gives me files with names foo-1.txt .. foo-1000.txt.
However, these files do not sort nicely, so I would like to zero-pad the $x variable, thus producing names of foo-0001.txt .. foo-1000.txt.

How to do that in zsh? (and bonus question, how to do it in bash?)

Answer 1

For reference sake, if you do not have control over the generation of the numeric values, you can do padding with:

% value=314 % echo ${(l:10::0:)value} 0000000314 % echo $value 314 

Answer 2

Use the -w flag to seq (in any shell):

$ seq -w 1 10 01 02 03 04 05 06 07 08 09 10