Dont think this would be a very good way to secure a box unless you secured all the poss ways to transfer a file to the box too (tftp, ftp, rcp, shares, email, ie bugs) or ppl could just transfer the file they need without echo.
as mentiond before you can @echo off to stop lines being displayd onto the screen.
or use a redirector to null to stop any programs reporting to cmd. ie
scan500 -p 139 xxx.xxx.xxx.xxx xxx.xxx.xxx.xxx > nul:
will send the display to null.
or another way to stop it all is to create a bat file and use the start command to run it
ie
start /b file.bat
this will launch the file.bat into the b/ground hide from the user and still run all the commands contained.
if wanting to secure a box. then I would copy cmd.exe to cmd1.exe say. then edit cmd.exe and remove ALL the comands. type/copy/echo etc. would cripple the cmd.exe but would serve the purpose.
and the last way to start a program thats hidden to the desktop user is to start as a service.
use srunner, svcany, firedaemon etc. setup a service and your program will run hiden. even programs that display a screen to windows etc. all be hidden