How to view who owns a file?

I know to change an owner you put

chown user:group file 

but what if I want to see who owns a file?

The issue I am having is I created a user at /var/www/new-user but when he uploads new files to there, they can't be viewed. I think I have to change the owner or group to www-data. Not positive.

I already have a user at /var/www/john that works fine. I thought I set the new on up the same. I wanted to compare mine and see whats different.

If you do ls -lh file you will see who owns it and what the permissions are. You could do ls -lh /var/www/ and compare the results between /var/www/john and /var/www/new-user.

To see the files ownership try ls -l

ls -l file
-rw-r--r-- 1 iain users 0 May  5 12:46 file

LS is probably the tool you want, but just to provide some additional variety. You could use

stat filename