最近做一些脚本自动化的事情，发现一个很有意思的东西，如下，如果用户账户包含了$符号，就会抛出一个“User cannot be found”的异常。
New-SPSite $CommunityUrl -OwnerAlias "ASIAPACIFIC`\$ExSquareDEV001" -Name "$CommunityName" -Template "STS#0" -ContentDatabase $CommunityDatabase
New-SPSite : User cannot be found.
上MSDN搜索了一下，发现了一篇文章讲述到了这个原因：http://technet.microsoft.com/en-us/library/ff730965.aspx
Quotation Marks in Windows PowerShell
First, let's review the basic distinction between single and double quotation marks in the Windows PowerShell language. It concerns the interpretation of variables.
-
Double quotes. When a command or expression that includes variables is enclosed in double quotes ("), the variables are replaced by their values before the command is executed.
-
Single quotes. When a command or expression that includes variables is enclosed in single quotes ('), the variables are not replaced by their values. Instead, they are interpreted literally.
There's actually a lot more to it – nested quotes and doubled quotes and escaped quotes and quotes in here-strings -- but these are the basics. For the rest, at the Windows PowerShell prompt, type:
-
get-help about_quoting_rules
大意是由于$是PowerShell变量的标志符号，所以不同的引号会做不同的处理。
双引号内的PowerShell变量会先计算出值，然后输出。
单引号内的PowerShell变量作为字符串直接输出。
看下面的一个示例：
使用双引号赋值，
变量赋值：$ExSquareServiceAccount = "ASIAPACIFIC\$ExSquareDEV001"
输出变量值：ASIAPACIFIC\
由于后面的认成了变量，而并没有赋值，这个时候就为空，输出就是前面的字符串了。
如果使用单引号，
变量赋值：$ExSquareServiceAccount = 'ASIAPACIFIC\$ExSquareDEV001'
输出变量值：ASIAPACIFIC\$ExSquareDEV001
整个字符串不会进行变量替换，直接输出。
