PowerTip of the Day from powershell.com上周汇总（十）

让powershell脚本在另外一个 powershell控制台运行的方法

Running Commands Elevated

http://powershell.com/cs/blogs/tips/archive/2010/09/27/running-commands-elevated.aspx

通过启动进程的方法

Start-Process powershell.exe -argumentlist '-command write-host "Hello world"' -verb runas

创建一个Event Logs

Creating New Event Logs

http://powershell.com/cs/blogs/tips/archive/2010/09/28/creating-new-event-logs.aspx

创建：

New-EventLog -LogName LogonScripts -Source ClientScripts

写：

Write-EventLog LogonScripts -Source ClientScripts -Message 'Test Message' -EventId 1234 -EntryType Warning

打开系统日志界面

Opening Event Log GUI

http://powershell.com/cs/blogs/tips/archive/2010/09/29/opening-event-log-gui.aspx

就一条命令：

Show-Eventlog

使用Write-Cmdlets需要注意的地方

Use Write-Cmdlets with Care!

http://powershell.com/cs/blogs/tips/archive/2010/09/30/use-write-cmdlets-with-care.aspx

下面的函数使用了两种不同的输出方法：

Function test

{

Write-Host "Result A"

"Result B"

}

当直接运行方法的时候，会得到所有的两个输出，但是write-host是直接输出到控制台的，所以这个值是无法通过变量获得的。

Test

Result A

Result B

$a = test

Result A

$a

Result B

Write-output方法

Do You Know Write-Output?

http://powershell.com/cs/blogs/tips/archive/2010/10/01/do-you-know-write-output.aspx

这个方法跟write-host不同，在函数里输出的值是可以在变量里获取到的。

Function testA

{

'My Result'

}

Function testB

{

Write-Output 'My Result'

}

Write-ouput需要注意的地方

Write-Output is Picky

http://powershell.com/cs/blogs/tips/archive/2010/10/04/write-output-is-picky.aspx

Function Convert-Dollar2EuroA($amount, $rate=0.8) {
$amount * $rate
}
Function Convert-Dollar2EuroB($amount, $rate=0.8) {
Write-Output $amount * $rate
}
Function Convert-Dollar2EuroC($amount, $rate=0.8) {
Write-Output ($amount * $rate)
}

注意其差别：

Convert-Dollar2EuroA 100
80
Convert-Dollar2EuroB 100
100
*
0,8
Convert-Dollar2EuroC 100
80

下载网页内容

Download Web Page Content

http://powershell.com/cs/blogs/tips/archive/2010/10/05/download-web-page-content.aspx

直接使用.net下的WebClient对象。

$url = 'http://blogs.msdn.com/b/powershell/'
$wc = New-Object System.Net.WebClient
$wc.DownloadString($url)

截取网页里的内容

Scraping Information from Web Pages

http://powershell.com/cs/blogs/tips/archive/2010/10/06/scraping-information-from-web-pages.aspx

通过正则表达式类：

$regex = [RegEx]'<div class="post-summary">(.*?)</div>'

$url = 'http://blogs.msdn.com/b/powershell/'
$wc = New-Object System.Net.WebClient
$content = $wc.DownloadString($url)

$regex.Matches($content) | Foreach-Object { $_.Groups[1].Value }

获取powershell团队博客的题目

Getting PowerShell Team Blog Topic Headers

http://powershell.com/cs/blogs/tips/archive/2010/10/07/getting-powershell-team-blog-topic-headers.aspx

还是通过正则：

$regex = [RegEx]'<span></span>(.*?)</a></h4>'

$url = 'http://blogs.msdn.com/b/powershell/'
$wc = New-Object System.Net.WebClient
$content = $wc.DownloadString($url)

$regex.Matches($content) | Foreach-Object { $_.Groups[1].Value }

使用Continue

Using 'Continue'

http://powershell.com/cs/blogs/tips/archive/2010/10/08/using-continue.aspx

温习循环结构中的Continue的用法。

For($x=1; $x -lt 20; $x++) {
If ($x % 4) { continue }
$x
}

以上来自powershell.com

2010年九月25日到十月8日的PowerTip of the Day