Can cat write to a file?

As for a vscript to help you, here is a rough example. We don't currently have a 'cat' api in the JavaScript API or an exact equivalent to do what you want, but this isn't too bad until we fix the other problem. This uses the code we use to fetch individual file versions that we use before launching one of the diff tools.

Hope this helps.

// the name of your repo.
var reponame = "vv10_public";

// the revision/changeset.  this must be the full HID of
// the desired changeset (not a unique prefix like --rev
// usually allows).
var rev      = "231e280789a007057ac37f5a5f471f2c19c95cb9";

// the repo-path of the file THAT IT HAD IN THAT CHANGESET.
// (one of the things that 'vv cat' does is try to allow
// you to specify a current path and reverse map it into
// the path as was at that point in the history (which 
// can get confusing if the file (and/or any parent directories)
// have been moved or renamed).)
var repopath = "@/LICENSE.txt";

// where you want the file created.
var output   = "/tmp/output.txt";

var repo = sg.open_repo( reponame );
var tne  = repo.get_treenode_info_by_path( rev, repopath );
// print( sg.to_json__pretty_print(tne) );
var temp = repo.fetch_blob_into_tempfile( tne.hid, true );
// print( sg.to_json__pretty_print(temp) );

sg.fs.move( temp.path, output );