Linux Bash 中的多线程
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Multithreading in Bash
提问by Kiran
I would like to introduce multithreading feature in my shell script.
我想在我的 shell 脚本中引入多线程功能。
I have a script which calls the function read_cfg()with different arguments.
Each of these function calls are independent.
我有一个脚本，它read_cfg()使用不同的参数调用函数。这些函数调用中的每一个都是独立的。
Would it be possible to instantiate these function calls (not scripts) parallelly. Please let me how can we achieve that.. ?
是否可以并行实例化这些函数调用（不是脚本）。请让我如何实现..？
采纳答案by Martin
Sure, just add &after the command:
当然，只需&在命令后添加：
read_cfg cfgA &
read_cfg cfgB &
read_cfg cfgC &
wait
all those jobs will then run in the background simultaneously. The optional waitcommand will then wait for all the jobs to finish.
然后所有这些作业将同时在后台运行。然后可选wait命令将等待所有作业完成。
Each command will run in a separate process, so it's technically not "multithreading", but I believe it solves your problem.
每个命令都将在单独的进程中运行，因此从技术上讲它不是“多线程”，但我相信它可以解决您的问题。
回答by mouviciel
Bash job control involves multiple processes, not multiple threads.
Bash 作业控制涉及多个进程，而不是多个线程。
You can execute a command in background with the &suffix.
您可以在后台执行带有&后缀的命令。
You can wait for completion of a background command with the waitcommand.
您可以使用该wait命令等待后台命令完成。
You can execute multiple commands in parallel by separating them with |. This provides also a synchronization mechanism, since stdout of a command at left of |is connected to stdin of command at right.
您可以通过将多个命令用 分隔来并行执行多个命令|。这也提供了一种同步机制，因为左侧命令的标准输出|连接到右侧命令的标准输入。
回答by tnorgd
You can run several copies of your script in parallel, each copy for different input data, e.g. to process all *.cfg files on 4 cores:
您可以并行运行脚本的多个副本，每个副本用于不同的输入数据，例如处理 4 个内核上的所有 *.cfg 文件：
ls *.cfg | xargs -P 4 -n 1 read_cfg.sh
The read_cfg.sh script takes just one parameters (as enforced by -n)
read_cfg.sh 脚本只接受一个参数（由 -n 强制执行）
