From a batch file I want to run a new tcc.exe (started) so that it completely replaces the process space of the current tcc.exe (starter). Is it possible? This is analogous to running a batch script without CALL from within a batch script; the former replaces the latter. What I'm after is something like the exec comand of the *nix bash shell http://ss64.com/bash/exec.html (just the bit about not creating a new process). Code: invoking process <=> starter tcc -> started tcc invoking process <=> started tcc So, started tcc inherits starter's PID, environment and console window, and returns exit status to the invoking process. Also note that starter and started tccs can be different versions.