Sounds like you didn't have a client spec set up. Any time you're operating on local files (so like when you're opening them for edit, or even when you're referring to files by a local relative path), the client spec defines how your local files correspond to the depot files. If you got the error I'm thinking of, it actually tells you exactly how to fix it!
C:\Perforce\test>p4 files ... Client 'subressors-computer' unknown - use 'client' command to create it.
If I already had a client spec set up on this computer, I could switch to it by running "p4 set P4CLIENT=that-client-name", but the error message is telling me that I can create a new client spec with the "client" command. Thanks for that tip, error message! Let me try that...
This brings up my text editor with my new client spec:
Client: subressors-computer Owner: subressor Description: Created by subressor Root: c:\Perforce\test Options: noallwrite noclobber nocompress unlocked nomodtime normdir SubmitOptions: submitunchanged LineEnd: local View: //depot/... //subressors-computer/...
The important parts of the client spec are the "Root" (which says where the client spec lives -- it defaults to my current directory) and the "View" (which says how the depot relates to the client root -- by default the entire depot is mapped, or all depots if you have more than one).
If I save this file and exit the editor, it saves the client spec:
C:\Perforce\test>p4 client Client subressors-computer saved.
Now I can run commands on files in my local directory! The client spec says that whenever I'm in C:\Perforce\test using this client spec on this computer, it's the same as being in //depot on the server.
C:\Perforce\test>p4 files ... //depot/foo/bleh#1 - branch change 147 (text) //depot/main/bleh#1 - branch change 148 (text)
I would recommend using the "p4 edit" method; "p4 retype" is not something that's meant for general or routine use.
Any command that operates on files can take a wildcard pattern -- in my previous post you saw how I used the pattern "b..." to say "open all files whose paths relative to this directory start with b for edit with the type of binary". You could also do "....txt" to say "all files under this directory that end in .txt", or "//depot/foo/....jpg" to say "all files that are in the //depot/foo directory whose names end in .jpg", or any combination you can imagine.