# Deferred file operations

To support self updating services, winsw offers a mechanism to perform file operations before the process you specified in the configuration file gets launched. 
This is often necessary because Windows prevents a file from being overwritten while it's in use.

To perform file operations, write a text file (in the UTF-8 encoding) at *myapp.copies* 
  (that is, it's in the same directory as *myapp.xml* and *myapp.exe* but with a different file extension), 
  and for each operation add one line:

* To move a file, write a line `src>dst`. If the `dst` file already exists it will be overwritten.

The success or failure of these operations will be recorded in the event log.

`src` and `dst` should be the full path to file, or you will see failed to copy file.

example:

```
c:\soft\sshd.exe.new>c:\bin\ssh.exe
```

The `<download>` element in the configuration file also provides an useful building block for a self updating service.