I am writing some scripts to update the Linux box\'s SVN repo with newer versions of xml files. The repo is huge, and there is no checkout version on the same box. The idea
You cannot update a file without checking out a folder locally. There's a shortcut however: in order not to checkout the whole repository, you could checkout only the sub-folder where the file you want to update is.
If your rep is at https://your.domain/myrep, you could check out https://your.domain/myrep/myfolder
That way, unless you have the XML file in the root folder, you would reduce the amount of files. If you have control over the repository, you could even create a sub-folder with the single purpose of storing that file.