PowerShell实现简单的grep功能

param($str, $path=".\") #输入参数，默认在当前目录及其子目录下查找
if([String]::IsNullOrEmpty($str)){
  Write-Output "Caution: input string is empty"
  exit
}
$path = Resolve-Path $path #获取绝对路径
if([System.IO.Directory]::Exists($path)){
  $subPathList = Get-ChildItem $path -Recurse *.* #获取所有子目录
  foreach($subPath in $subPathList){
    $subPath = $subPath.FullName
    if([System.IO.Directory]::Exists($subPath)){
      Continue
    }
    $foundArr = Select-String -path $subPath -Pattern $str
    foreach($found in $foundArr)
    {
      if($found -match "(.+:\d+):") #删除行号后面的内容
      {
        Write-Output $matches[1]
      }
    }
  }
}elseif([system.IO.File]::Exists($path)){
  $foundArr = Select-String -path $path -Pattern $str
  foreach($found in $foundArr)
  {
    if($found -match "(.+:\d+):")
    {
      Write-Output $matches[1]
    }
  }
}