Marcus Jensen asked me a very interesting question:
I want to send 3 lines of configuration to a remote router, but I know the first line will kill my connection. Can I save these 3 lines of code to a text file, and then issue a Tcl command to add those to the running config?
The solution is much simpler and does not have to involve Tcl at all. The copy something system:running-config command merges the configuration commands in the source file with the current running configuration.
You can store the configuration commands you want to execute in a local file (even in NVRAM) or you could execute them directly off a file server (using HTTP, FTP, TFTP or SCP protocol).