A single file upload involves so few commands that it is enough to provide them on the command line, saving writing a script file:
winscp.com /command "open sftp://user:[email protected]/" "put examplefile.txt /home/user/" "exit"
However you may want to use a script file anyway, so you can later expand it:
open sftp://user:[email protected]/
put examplefile.txt /home/user/
To run the script use following command (providing you have saved the script to file example.txt):