先进先出进程数，持续增长

Question

有趣的方法，所以我遵循了它。

我有一个说明操作的诊断脚本。特别是，它为每个 Tick（“允许运行”）标记了序列号和时间，例如[4] Sent 19:53:54，因此当读取时，可以识别它。当序列结束时shfiles.txt，我也会刷新剩余的蜱虫。

我还用前缀标记了所有调试[ x ] &&。这些行可以永久删除，或者只是通过将 x 更改为空格来禁用。我更改了所有文件名。

我的命令文件moonie.cmds是这样的（每个命令都标识自己并使调度变得不规则）：

echo One && sleep 8
echo Two && sleep 3
echo Three && sleep 6
echo Four && sleep 5
echo Five && sleep 9

这些是简单的命令，我使用bash -c.脚本名称应该没问题，但 .cmds 文件中的参数和引用可能很困难。我不明白为什么你的mv脚本（？）运行后到另一个目录，因为我不知道你的.cmds文件是什么样的。

我曾经pstree展示过，我的 bash 和外部脚本 pid 是恒定的，异步子 shell 和 sleep 一次运行两个，由变量配置threads。我用 1、2、3 和 10 个线程进行了测试。

我的脚本是这样的：

#! /bin/bash

Threads=2

mkdir -p moonie.dir     #.. Not used.

#.. Clean the named pipe and attach to fd9. 
rm -f moonie.fifo
mkfifo moonie.fifo
exec 9<>moonie.fifo
 
#.. Seed the fifo with required thread count.
for ((Seq = 1; Seq <= Threads; ++Seq)); do
    printf '[%s] Sent %(%T)T\n' "${Seq}" -1 >&9
done

echo "================ start sh ===================="

[ x ] && sleep 1    #.. Show we are waiting for the Ticks.

while IFS='' read -r Cmd; do    #.. Work through the command list.

    IFS='' read -r -u 9 Tick    #.. Wait for a free thread. 
    [ x ] && printf '%(%T)T Read Tick %s\n' -1 "${Tick}"

    {   #.. Launch a thread asynchronously.
        [ x ] && printf '%(%T)T Begin %s\n' -1 "${Cmd}"
        bash -c "${Cmd}"
        [ x ] && printf '%(%T)T Ended %s\n' -1 "${Cmd}"
        #.. Refresh its thread on completion.
        printf '[%s] Sent %(%T)T\n' "${Seq}" -1 >&9
    } &
    (( ++Seq ))     #.. Number Ticks for diagnostics.

    [ x ] && sleep 0.3              #.. Wait for the job to register.
    [ x ] && pstree -p "${PPID}"    #.. Show the running job hierarchy.

done < moonie.cmds

wait    #.. Wait for all threads to complete.

#.. Flush superfluous Ticks (timeout read because the fifo will hang).
while IFS='' read -r -t 1 -u 9 Tick; do
    [ x ] && printf '%(%T)T Discard Tick %s\n' -1 "${Tick}"
done

exec 9>&-       #.. Disconnect and remove the fifo.
rm moonie.fifo

echo "================= done ===================="
exit 0

调试会话是这样的：

================ start sh ====================
19:53:51 Read Tick [1] Sent 19:53:50
19:53:51 Begin echo One && sleep 8
One
bash(12037)───moonie(16150)─┬─moonie(16155)───sleep(16157)
                            └─pstree(16158)
19:53:51 Read Tick [2] Sent 19:53:50
19:53:51 Begin echo Two && sleep 3
Two
bash(12037)───moonie(16150)─┬─moonie(16155)───sleep(16157)
                            ├─moonie(16159)───sleep(16161)
                            └─pstree(16162)
19:53:54 Ended echo Two && sleep 3
19:53:54 Read Tick [4] Sent 19:53:54
19:53:54 Begin echo Three && sleep 6
Three
bash(12037)───moonie(16150)─┬─moonie(16155)───sleep(16157)
                            ├─moonie(16164)───sleep(16166)
                            └─pstree(16167)
19:53:59 Ended echo One && sleep 8
19:53:59 Read Tick [3] Sent 19:53:59
19:53:59 Begin echo Four && sleep 5
Four
bash(12037)───moonie(16150)─┬─moonie(16164)───sleep(16166)
                            ├─moonie(16168)───sleep(16170)
                            └─pstree(16171)
19:54:00 Ended echo Three && sleep 6
19:54:00 Read Tick [5] Sent 19:54:00
19:54:00 Begin echo Five && sleep 9
Five
bash(12037)───moonie(16150)─┬─moonie(16168)───sleep(16170)
                            ├─moonie(16172)───sleep(16174)
                            └─pstree(16175)
19:54:04 Ended echo Four && sleep 5
19:54:09 Ended echo Five && sleep 9
19:54:09 Discard Tick [6] Sent 19:54:04
19:54:09 Discard Tick [7] Sent 19:54:09
================= done ====================

Answer 1