[sbron] 16 Aug 2005: In the [Tcl chatroom] [Donal Fellows] provided a method for a script to restart itself in the background. It goes something like this:

 if {[lindex $argv 0] ne "-dorealprocessing"} {
     set command [list [info nameofexecutable]]
     # A starpack doesn't use a script parameter on the command line
     if {![info exists ::starkit::mode] || $starkit::mode ne "starpack"} {
         lappend command [info script]
     }
     eval exec $command -dorealprocessing $argv >/dev/null &
     exit
 }
 # The real code goes here ...

This code simply restarts the shell that's executing the script in the background with one additional parameter and then exits. This should of course only be done when the additional parameter is not present to prevent an endless sequence of new processes.