FIFOのプロセスの交換またはコマンドの実行はいつ開始され、終了しますか？

Bashで実験的に：

$ strace -tttfe execve bash -c 'sleep 5 <(sleep 6)'
1522025733.188859 execve("/bin/bash", ["bash", "-c", "sleep 5 <(sleep 6)"], [/* 41 vars */]) = 0
strace: Process 24248 attached
[pid 24247] 1522025733.215188 execve("/bin/sleep", ["sleep", "5", "/dev/fd/63"], [/* 41 vars */]) = 0
strace: Process 24249 attached
[pid 24249] 1522025733.218331 execve("/bin/sleep", ["sleep", "6"], [/* 41 vars */]) = 0
sleep: invalid time interval ‘/dev/fd/63’
Try 'sleep --help' for more information.
[pid 24247] 1522025733.227459 +++ exited with 1 +++
[pid 24249] 1522025739.230933 +++ exited with 0 +++
1522025739.232270 --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=24249, si_uid=1000, si_status=0, si_utime=0, si_stime=0} ---
1522025739.233169 +++ exited with 0 +++
$ strace -tttfe execve bash -c 'sleep 5 >(sleep 6)'
1522025752.162876 execve("/bin/bash", ["bash", "-c", "sleep 5 >(sleep 6)"], [/* 41 vars */]) = 0
strace: Process 24253 attached
[pid 24252] 1522025752.188413 execve("/bin/sleep", ["sleep", "5", "/dev/fd/63"], [/* 41 vars */]) = 0
strace: Process 24254 attached
[pid 24254] 1522025752.191032 execve("/bin/sleep", ["sleep", "6"], [/* 41 vars */]) = 0
sleep: invalid time interval ‘/dev/fd/63’
Try 'sleep --help' for more information.
[pid 24252] 1522025752.197213 +++ exited with 1 +++
[pid 24254] 1522025758.197114 +++ exited with 0 +++
1522025758.197959 --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=24254, si_uid=1000, si_status=0, si_utime=0, si_stime=0} ---
1522025758.198820 +++ exited with 0 +++

command1そしてそれぞれの後に始めますcommand3。command2command4

彼らは出るか死ぬ条件が満たされる限り出て行きます。

makefifo fifo1; prog2 < fifo1 &; prog1 > fifo1;makefifo fifo2; prog3 > fifo12 &; prog2 < fifo2;少なくともbashでは構文エラーです。それ以外の場合でも、リダイレクトがない場合とは異なる実行順序を生成するリダイレクトには何も表示されません。