显示正在运行的PowerShell脚本中的所有环境变量

Question

我需要在运行时在PowerShell脚本中显示所有已配置的环境变量.通常在显示环境变量时,我可以在shell中使用以下其中一种(除了其他技术,但这些很简单):

gci env:*
ls Env:

但是,我从另一个程序调用了一个脚本,当我在脚本中使用上述调用之一时,而不是显示环境变量及其值,而是获取System.Collections.DictionaryEntry类型列表而不是变量及其值.在PowerShell脚本中,如何显示所有环境变量？

Answer 1

更短的版本:

gci env:* | sort-object name

这将显示名称和值.

Answer 2

最短版本(变量按名称排序):

gci env:

Answer 3

我认为所提供的任何答案都与该问题无关。OP 正在获取对象类型列表（每个成员都相同），而不是实际的变量名称和值。这就是你所追求的：

gci env:* | select Name,Value

短缺：

Get-ChildItem Env:* | Select-Object -Property Name,Value

Answer 4

我终于通过遍历字典中的每个条目来摸索我的方式:

(gci env:*).GetEnumerator() | Sort-Object Name | Out-String

Answer 5

该命令也有效：

dir env:

Answer 6

带有通配符过滤器的简短版本：

gci env: | where name -like 'Pro*'

Answer 7

默认情况下，长环境变量值会被截断。

这是获取具有完整值的环境变量排序列表的一种快速方法：

Get-ChildItem env:* | Sort-Object Name | Format-List

Answer 8

tl;dr

Since you were looking for a friendly string representation of the environment-variable name-value pairs:

gci env: | oss

oss is a built-in wrapper function for Out-String -Stream, and therefore returns each name-value pair as its own string; pipe to Out-String (without -Stream) to get a single, multi-line string (albeit one that invariably and unexpectedly has a trailing newline - see GitHub issue #14444).

To list the names and values of all environment variables in PowerShell, sorted by name,^[1] list the content (child items) of the env: PowerShell drive using the Get-ChildItem cmdlet (a built-in alias of which is gci):

# 'gci' is a built-in alias of the 'Get-ChildItem' cmdlet.
# Avoid alias 'ls', because on Unix-like platforms 
# it isn't defined and instead refers to the standard utility of that name.
# The output is implicitly *sorted by variable name*.
gci env:

# Use *wildcards* to list variables by *name pattern*; e.g, all whose
# name starts with "home"
gci env:home*

The above outputs objects, namely instances of [System.Collections.DictionaryEntry] describing each variable as a name-value pair, with .Key (.Name) and .Value properties. PowerShell's for-display formatting system automatically renders these in a friendly two-column format.

• To list environment-variable names only:

  gci env: -Name
  
  # Alternative, using property access:
  (gci env:).Name
  

• To get a specific environment variable's value, e.g. the value of USERNAME, it's easiest to use namespace variable notation:

  # Output the value of environment variable "USERNAME"
  $env:USERNAME
  
  # Alternative, using gc (alias of Get-Content)
  # Needed if the name is stored in a variable.
  gc env:USERNAME
  

If you stringify these objects with (potentially implied) .ToString():

• In Windows PowerShell, they uselessly stringify as their type name, i.e. as verbatim 'System.Collections.DictionaryEntry'

• In PowerShell (Core) 7, they now more meaningfully stringify as '[<name>, <value>]'

• Try with (% is a built-in alias of the ForEach-Object cmdlet):

  gci env: | % tostring
  
  # Ditto with Write-Host, which also uses .ToString() stringification
  gci env: | Write-Host
  

If you want to stringify them as they would print to the display, using the friendly two-column format, use the Out-String cmdlet:

# Outputs *friendly* string representations
gci env: | oss # 'oss' is a built-in wrapper function for 'Out-String -Stream'

Note: If you use Out-String without -Stream, you get a single, multi-line string as the output, though note that it will have a trailing newline.^[2]

^{[1] Note that using Get-ChildItem / gci with env:*, i.e. wildcard character * following the drive specification env: - is not only unnecessary for getting all variables, it actually results in unsorted output.}

^{[2] That a trailing newline is invariably appended is problematic, as discussed in GitHub issue #14444}

Answer 9

Powershell中有多种获取所有环境变量的方法

 [System.Environment]::GetEnvironmentVariables()
 or
 dir env:

通过名称获取环境变量

[System.Environment]::GetEnvironmentVariable("USERNAME")
 $env:USERNAME