Is it possible to access all the registered user IDs in OSM?

I mean only the IDs, no other information. Because at this web page: http://wiki.openstreetmap.org/wiki/Stats, there is the stat of number of users. Any suggestion?

Many thanks in advance.

Just the numbers?
If you are using Linux, you can get the ids very easily. Look at the description of these commands:
cut
sed
grep

First, you would have to download the .osm file (or .pbf) of the region you chose.

This will not provide a list of all registered user ids, because only some of the registered users have actually ever edited anything.

@Marqqs: thank you for your help.
@Tordanik: that’s true, thanks.

You’re right, of course. You would need the “full planet”.
Maybe there is a plain user list available too? I’m not sure…

xintao:

If you need help with these commands, just ask. I never tried, but I think it should be possible to extract the necessary information with these commands. A few other commands which could be helpful:
sort
wc
tr

P.S.:
First try the tool chain on a small part of the file. Here, these could help:
head
tail