Good choice to use File::Temp and the list form of system, but don't forget to check its return value - like system(...)==0 or die "system failed, \$?=$?";

Not very elegant thought...

I think this is a case where reliability is elegant :-) Temp files are unlikely to have filename conflicts, are created in locations where they don't disturb the user (unlike some programs that create temp files in the user's home directory and/or use fixed names), and you get automatic cleanup (although I'm not sure why you set UNLINK=>0). Overall they're a good solution, and in fact IPC::Run3 makes heavy use of them, AFAIK it's one of the reasons it's so portable.