Following problem, i have photos from two cameras sorted by date taken, which i want to represent in the right order. How would the command be,
to add some preceding numbering to those files, starting from 01, so that the first file from the list (the oldest file) would have the prefix 01 - old name.jpg,
the second file 02 - old name.jpg & so on?
From the rename dialog: Numbering Files.
For doing it in a command, see the Rename command's NUMBER argument, which has an example that's almost the same as what you're doing.
Thanks, but it's still not clear. Foloowing command works:
Rename PATTERN * TO [#2] * NUMBER
But the " - ", how would i include that? I've tried
Rename PATTERN * TO [#2] - * NUMBER
or
Rename PATTERN * TO [#2 - ]* NUMBER
but i can't figure out, where exactly to put that part.
You need quotes around arguments with spaces in them.
I tried that too, with single quotes ' , & also double quotes ", but the rename dialog keeps coming up then. I also tried to place them
after the first set of brackets, but i still have no idea, where to place them otherwise. 
Rename PATTERN * TO [#2 ' - '] * NUMBER
Always double-quotes, around the whole argument:
Rename PATTERN * TO "[#2] - *" NUMBER
Cool, that works 
, thanks! So the quotes must be around the whole expression & double. I must have them mixed up with
the single quotes used in date buttons, like dd'-'MMM'-'yy.
I don't think you need those. dd-MMM-yy works on its own, at least in the two places I can think of.