Underhanded launcher
Tcl

Simple.

proc main {} {
    set fd [open filenames.txt]
    while {[gets $fd line] ne ""} {
        set other [open $line w]
        puts $other [clock format [clock seconds]]
    }
}
main



   Ilmari Karonen is right:
 If you supply a filename with a | as first character, it will treat the rest as command. IIRC for Perl it has to be at the end.