1) Do I have to leave the spaces in attrib +h *.dop between attrib and + and h and *?
Yes, there is a indeed a space between them.
2) Will it work in all subfolders (I have a LOT of folders in which these pesky files are visible)?
You'll have to edit the bat file to change to the directory first i.e. add
before the attrib line.
Someone correct me if i'm wrong.
3) If I need to see them again, just restart the computer?
Restarting won't do as the 'hidden' attribute has been added to the files. You'll have to either select 'Show hidden files and folders' from Tools>Folder options or edit the bat file w/ the +h replaced w/ -h.
Oops! I just realized that the file extension is .CR2.dop and I'm worried that I'd hide all the .CR2 files....
The extension of this type of file would still be .dop. Windows treats the words after the last dot as extension.