How can I allow users on a vps to downoad and upload files?
 

I need to allow users on a hosted VPS to download the files from their home directory, edit these files and upload them back to that directory.

This may be done over a period of time in which the user may shut down his/her pc.

The OS they use is unknown.

Can that be done with HTML? How? (I can write CGI programs, I can also envisage the use of 'forms' but not clearly.)

If not, how can I make it as simple as possible for the user?

Thank you for your help.

Is there some reason they can't use scp/sftp/ftp ?

Yes, their lack of knowledge.

The process you described (download-edit-upload) won't get any simpler by making it a web app, if the user could be the authoritative source then possibly you could set up a regular sync of some kind

Thank you for your answers.