Tclx provides a binding to execl .

execl ?-argv0 argv0? prog ?arglist?

Do an execl, replacing the current program (either Extended Tcl or an application with Extended Tcl embedded into it) with prog and passing the arguments in the list arglist. If -argv0 is specified, the zero'th argument will be argv0 instead of the usual default (i.e., prog).

Note that if this command fails, it will not be save to use Tk from the current process any more.

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