PowerShell 脚本块内的命令执行顺序 [英] command execution ordering inside a PowerShell scriptblock

问题描述

一开始我对 PowerShell ScriptBlock 感到兴奋，但最近我对它在块内的执行顺序感到困惑.例如:

I got excited with PowerShell ScriptBlock at first but I was confused recently with its executing ordering inside blocks. For example:

$test_block = {
  write-host "show 1"
  ps
  write-host "show 2"
  Get-Date
}

调用 $test_block.Invoke() 的输出:

The output by calling $test_block.Invoke():

show 1
show 2
<result of command 'ps'>
<result of command 'get-date'>

输出内容的命令会先运行吗?

Do commands who output something run first?

推荐答案

这种行为是因为 write-主机 不会将输出放在管道上.其他命令放置在管道上，因此在函数(调用)返回之前不会输出到屏幕.

This behaviour is because write-host doesn't put the output on the pipeline. The other commands are placed on the pipeline so are not output to the screen until the function (invoke) returns.

要获得我认为您期望的行为，请改用 write-output，所有命令的结果将在管道中返回.

To get the behaviour I believe you were expecting, use write-output instead, the results of all the commands will then be returned in the pipeline.

$test_block = {
  write-output "show 1"
  ps
  write-output "show 2"
  Get-Date
}

$test_block.Invoke()

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