[Expect] includes a fork.  So does [TclX].

Example:
    for {set i 0} {$i < 100} {incr i} {
        set pid [fork]
        switch $pid {
            -1 {
                puts "Fork attempt #$i failed."
            }
            0 {
                puts "I am child process #$i."
                exit
            }
            default {
                puts "The parent just spawned child process #$i."
            }
        }
    }

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An other example script using fork is a unix style [daemon].
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[Category Example]