No. You have to add the file names you want to work with after the command. In your case you want to work with all files, so append an asterisk (*). Also, add a file extension to 'i' if you want to create a backup:

...will create a copy of each file with a .bak extension before performing the search/replace. If you only want to affect certain files, name them explicitly, or use glob patterns. For instance, the following will only work on files with a .txt extension:

That depends entirely upon the shell. Bash will turn *.txt into a list of files. cmd.exe will not.

This doesn't seem to be working...

Can't open *: Invalid argument.

--perl.j

To tame the cmd you could use the brilliant idea which I read by BrowserUK (cannot find the link just now) - the following one-liner works on my windows pc:

perl -pi.bak -e "BEGIN{@ARGV=map{glob}@ARGV;}s/5/6/g;" *
[download]

A wild guess: On Windows, you used to have to use *.* to match all files, while a single * would only match files with no extension. Is that still the case?

Aaron B.
My Woefully Neglected Blog, where I occasionally mention Perl.