PowerShell中Get-FileHash用变量路径报错，直接指定路径正常的问题排查

问题描述 #

执行以下代码生成文件哈希时出现报错：

$newHash = (Get-FileHash $PathToFile -Algorithm $Algorithm).hash

错误提示：

Get-FileHash: Cannot find the path '/Users/name/Downloads' /Users/name/Downloads/filename.txt'' because it does not exist.

但直接硬编码文件路径运行相同逻辑却能正常工作：

$newHash = (Get-FileHash '/Users/name/Downloads/filename.txt' -Algorithm $Algorithm).hash

完整原始代码如下：

$VendorHash = Read-Host -Prompt "Paste hash here.."

if ($VendorHash) {
    Write-Host "Continue.." 
  } else {
    Write-Warning -Message "You must paste hash here.."
}
    
$PathToFile = Read-Host -Prompt "Drop file here.."
$Algorithm = Read-Host -Prompt "Enter algorithm.."
    
if ($PathToFile) {
    Write-Host "Generating hash please wait.."
  } else {
    Write-Warning -Message "Path to file is missing.."
}

$NewHash = (Get-FileHash -Path $PathToFile -Algorithm $Algorithm).hash

Compare-Object -ReferenceObject $VendorHash -DifferenceObject $NewHash

报错原因 #

当你在macOS终端拖拽文件到Read-Host输入框时，系统会自动给路径添加单引号（如果路径含空格还会额外处理），但Read-Host会把这些单引号一并读取为字符串的一部分。比如$PathToFile的实际值是'/Users/name/Downloads/filename.txt'（带首尾单引号），传给Get-FileHash时，PowerShell会把单引号当成路径的一部分，导致路径格式错乱，出现无效的路径字符串。

解决方法 #

在获取$PathToFile后，添加代码去除字符串首尾的单引号或双引号，确保路径是纯净的有效路径：

修正后的完整代码 #

$VendorHash = Read-Host -Prompt "Paste hash here.."

if ($VendorHash) {
    Write-Host "Continue.." 
  } else {
    Write-Warning -Message "You must paste hash here.."
}
    
$PathToFile = Read-Host -Prompt "Drop file here.."
# 去除路径首尾的单引号和双引号
$PathToFile = $PathToFile.Trim("'""")
$Algorithm = Read-Host -Prompt "Enter algorithm.."
    
if ($PathToFile) {
    Write-Host "Generating hash please wait.."
  } else {
    Write-Warning -Message "Path to file is missing.."
}

# 额外添加路径存在校验，增强健壮性
if (Test-Path -Path $PathToFile) {
    $NewHash = (Get-FileHash -Path $PathToFile -Algorithm $Algorithm).hash
    Compare-Object -ReferenceObject $VendorHash -DifferenceObject $NewHash
} else {
    Write-Warning "File path does not exist: $PathToFile"
}

内容的提问来源于stack exchange，提问作者mrn3ff