PowerShellコマンドの基本 ── まず覚える操作と安全な使い方

探す → 見る → 絞る → 並べる → 出力する → 必要なら変更する

Get-ChildItem

Get-ChildItem -File |
  Where-Object { $_.LastWriteTime -gt (Get-Date).AddDays(-7) } |
  Sort-Object LastWriteTime -Descending |
  Select-Object Name, Length, LastWriteTime

$PSVersionTable

#Requires -Version 7.0

Get-Process
Get-Service
Get-ChildItem
Copy-Item
Remove-Item
Export-Csv

Get-Command dir

# 読めるが、スクリプトでは避けたい
ls *.log

# 意図が明確
Get-ChildItem -Filter *.log

# Process という名詞を持つコマンドを探す
Get-Command -Noun Process

# Service 関連のコマンドを探す
Get-Command *Service*

# CSV 関連のコマンドを探す
Get-Command *Csv*

Get-Command *Item*
Get-Command *Content*
Get-Command *Json*

Get-Help Get-ChildItem
Get-Help Get-ChildItem -Examples
Get-Help Get-ChildItem -Full
Get-Help Get-ChildItem -Online

Get-Help Where-Object -Examples

Update-Help

Get-Process | Get-Member
Get-Service | Get-Member
Get-ChildItem | Get-Member

Get-Service | Select-Object Name, Status

Get-ChildItem -File | Select-Object Name, Length, LastWriteTime

Get-Process | Sort-Object CPU -Descending | Select-Object -First 10

プロセス一覧を取得
  → CPU 使用量で降順に並べる
  → 上位10件だけ表示

# 停止中のサービスだけ表示
Get-Service | Where-Object { $_.Status -eq "Stopped" }

# 100MB を超えるファイルだけ表示
Get-ChildItem -File |
  Where-Object { $_.Length -gt 100MB }

# 名前に backup を含むファイルだけ表示
Get-ChildItem -File |
  Where-Object { $_.Name -like "*backup*" }

Where-Object { $_.Length -gt 100MB }

Get-Service | Where-Object Status -EQ "Stopped"

Get-Service | Where-Object { $_.Status -eq "Stopped" }

# メモリ使用量の大きい順
Get-Process |
  Sort-Object WorkingSet -Descending |
  Select-Object -First 10 Name, Id, WorkingSet

# 更新日時の新しい順
Get-ChildItem -File |
  Sort-Object LastWriteTime -Descending |
  Select-Object -First 20 Name, LastWriteTime

Get-Process |
  Select-Object Name, Id, CPU, WorkingSet

Get-Process | Select-Object -First 5
Get-Process | Select-Object -Last 5

Get-Service |
  Select-Object Name, DisplayName, Status, StartType |
  Export-Csv .\services.csv -NoTypeInformation -Encoding UTF8

Format-Table
Format-List
Format-Wide

# 避ける: CSV に表示用情報が混ざる
Get-Process |
  Format-Table Name, CPU |
  Export-Csv .\process.csv -NoTypeInformation

# 正しい: 先にプロパティを選んで CSV 出力
Get-Process |
  Select-Object Name, CPU |
  Export-Csv .\process.csv -NoTypeInformation -Encoding UTF8

Get-Location

Set-Location C:\Work

Set-Location "C:\Work Files\Reports"

Get-ChildItem
Get-ChildItem -File
Get-ChildItem -Directory
Get-ChildItem -Recurse

Get-ChildItem -Filter *.log

Get-ChildItem C:\Logs -Filter *.log -Recurse

# フォルダー作成
New-Item -ItemType Directory -Path .\archive

# 空ファイル作成
New-Item -ItemType File -Path .\memo.txt

if (-not (Test-Path .\archive)) {
  New-Item -ItemType Directory -Path .\archive
}

Copy-Item .\report.xlsx .\backup\report.xlsx

Copy-Item .\data .\backup\data -Recurse

Copy-Item .\data .\backup\data -Recurse -WhatIf

Move-Item .\old.log .\archive\old.log

Get-ChildItem .\logs -Filter *.log |
  Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-30) } |
  Move-Item -Destination .\archive -WhatIf

Get-ChildItem .\logs -Filter *.log |
  Where-Object { $_.LastWriteTime -lt (Get-Date).AddDays(-30) } |
  Move-Item -Destination .\archive

Remove-Item .\old.log -WhatIf

Remove-Item .\old.log

# まず対象を確認
Get-ChildItem C:\Logs -Filter *.tmp -Recurse |
  Select-Object FullName, Length, LastWriteTime

# 次に削除予定を確認
Get-ChildItem C:\Logs -Filter *.tmp -Recurse |
  Remove-Item -WhatIf

# 最後に実行
Get-ChildItem C:\Logs -Filter *.tmp -Recurse |
  Remove-Item

Get-Content .\app.log

Get-Content .\app.log -Tail 50

Get-Content .\app.log -Tail 20 -Wait

Select-String -Path .\app.log -Pattern "ERROR"

Select-String -Path .\logs\*.log -Pattern "ERROR", "WARN"

Select-String -Path .\logs\*.log -Pattern "ERROR" |
  Select-Object Path, LineNumber, Line |
  Export-Csv .\error-lines.csv -NoTypeInformation -Encoding UTF8

"hello" | Set-Content .\memo.txt -Encoding UTF8
"next line" | Add-Content .\memo.txt -Encoding UTF8

Get-Process |
  Select-Object Name, Id, CPU |
  Export-Csv .\process.csv -NoTypeInformation -Encoding UTF8

$users = Import-Csv .\users.csv
$users

$users | Select-Object Name, Department

$users |
  Where-Object { $_.Department -eq "Sales" }

$users |
  Where-Object { $_.Enabled -eq "true" }

$users |
  Where-Object { $_.Department -eq "Sales" } |
  Export-Csv .\sales-users.csv -NoTypeInformation -Encoding UTF8

# 避ける
$users | Format-Table | Export-Csv .\out.csv -NoTypeInformation

# 正しい
$users | Select-Object Name, Department, Enabled | Export-Csv .\out.csv -NoTypeInformation -Encoding UTF8

$data = Get-Content .\settings.json -Raw | ConvertFrom-Json
$data

[pscustomobject]@{
  Name = "BatchJob"
  Enabled = $true
  Retry = 3
} | ConvertTo-Json

$config | ConvertTo-Json -Depth 10 | Set-Content .\settings.json -Encoding UTF8

Get-Process

Get-Process |
  Sort-Object WorkingSet -Descending |
  Select-Object -First 10 Name, Id, WorkingSet

Get-Process -Name notepad

Stop-Process -Name notepad -WhatIf

Stop-Process -Name notepad

Get-Service

Get-Service |
  Where-Object { $_.Status -eq "Stopped" }

Get-Service -Name "Spooler"

Get-Service -Name "Spooler"
Restart-Service -Name "Spooler" -WhatIf

Get-WinEvent -LogName System -MaxEvents 100 |
  Where-Object { $_.LevelDisplayName -eq "Error" } |
  Select-Object TimeCreated, ProviderName, Id, Message

Get-WinEvent -LogName System -MaxEvents 1 | Format-List *

Get-WinEvent -LogName Application -MaxEvents 50 |
  Select-Object TimeCreated, ProviderName, Id, LevelDisplayName, Message

$start = (Get-Date).AddHours(-24)

Get-WinEvent -FilterHashtable @{
  LogName = "System"
  StartTime = $start
} |
  Select-Object TimeCreated, ProviderName, Id, LevelDisplayName, Message

Get-WinEvent -LogName System -MaxEvents 500 |
  Where-Object { $_.LevelDisplayName -in @("Error", "Warning") } |
  Select-Object TimeCreated, ProviderName, Id, LevelDisplayName, Message |
  Export-Csv .\system-events.csv -NoTypeInformation -Encoding UTF8

$path = "C:\Logs"
Get-ChildItem $path

$today = Get-Date
$limit = (Get-Date).AddDays(-30)

$extensions = @("*.log", "*.txt", "*.csv")

foreach ($ext in $extensions) {
  Get-ChildItem C:\Work -Filter $ext
}

$params = @{
  Path = "C:\Logs"
  Filter = "*.log"
  Recurse = $true
}

Get-ChildItem @params

[pscustomobject]@{
  ComputerName = $env:COMPUTERNAME
  UserName     = $env:USERNAME
  CheckedAt    = Get-Date
}

Get-ChildItem C:\Logs -Filter *.log |
  ForEach-Object {
    [pscustomobject]@{
      Name          = $_.Name
      FullName      = $_.FullName
      SizeMB        = [math]::Round($_.Length / 1MB, 2)
      LastWriteTime = $_.LastWriteTime
    }
  } |
  Export-Csv .\log-files.csv -NoTypeInformation -Encoding UTF8

# Find-OldLogs.ps1
param(
  [string]$Path = "C:\Logs",
  [int]$Days = 30,
  [string]$OutputPath = ".\old-logs.csv"
)

$limit = (Get-Date).AddDays(-$Days)

Get-ChildItem -Path $Path -Filter *.log -File -Recurse |
  Where-Object { $_.LastWriteTime -lt $limit } |
  Select-Object FullName, Length, LastWriteTime |
  Export-Csv -Path $OutputPath -NoTypeInformation -Encoding UTF8

Write-Host "Exported: $OutputPath"

.\Find-OldLogs.ps1 -Path C:\Logs -Days 60 -OutputPath .\old-logs.csv

Get-ExecutionPolicy
Get-ExecutionPolicy -List

Set-ExecutionPolicy -ExecutionPolicy RemoteSigned -Scope CurrentUser

try {
  Copy-Item .\source.txt .\backup\source.txt -ErrorAction Stop
  Write-Host "Copy succeeded"
}
catch {
  Write-Error "Copy failed: $($_.Exception.Message)"
}

$results = foreach ($file in Get-ChildItem .\input -File) {
  try {
    Copy-Item $file.FullName .\backup -ErrorAction Stop

    [pscustomobject]@{
      FileName = $file.Name
      Status   = "OK"
      Message  = ""
    }
  }
  catch {
    [pscustomobject]@{
      FileName = $file.Name
      Status   = "NG"
      Message  = $_.Exception.Message
    }
  }
}

$results | Export-Csv .\copy-result.csv -NoTypeInformation -Encoding UTF8

1. Get 系で対象を見る
2. Where-Object で絞る
3. Select-Object で対象一覧を確認する
4. Export-Csv で記録する
5. -WhatIf で変更予定を確認する
6. 本実行する

Get-ChildItem C:\Temp -Filter *.tmp -File -Recurse

$limit = (Get-Date).AddDays(-30)

Get-ChildItem C:\Temp -Filter *.tmp -File -Recurse |
  Where-Object { $_.LastWriteTime -lt $limit }

$targets = Get-ChildItem C:\Temp -Filter *.tmp -File -Recurse |
  Where-Object { $_.LastWriteTime -lt $limit }

$targets |
  Select-Object FullName, Length, LastWriteTime

$targets |
  Select-Object FullName, Length, LastWriteTime |
  Export-Csv .\delete-targets.csv -NoTypeInformation -Encoding UTF8

$targets | Remove-Item -WhatIf

$targets | Remove-Item

Get-ChildItem C:\App\Logs -Filter *.log -File -Recurse

$since = (Get-Date).AddDays(-7)

Get-ChildItem C:\App\Logs -Filter *.log -File -Recurse |
  Where-Object { $_.LastWriteTime -ge $since }

$since = (Get-Date).AddDays(-7)

Get-ChildItem C:\App\Logs -Filter *.log -File -Recurse |
  Where-Object { $_.LastWriteTime -ge $since } |
  Select-String -Pattern "ERROR"

$since = (Get-Date).AddDays(-7)

Get-ChildItem C:\App\Logs -Filter *.log -File -Recurse |
  Where-Object { $_.LastWriteTime -ge $since } |
  Select-String -Pattern "ERROR" |
  Select-Object Path, LineNumber, Line |
  Export-Csv .\error-report.csv -NoTypeInformation -Encoding UTF8

# Export-ErrorReport.ps1
param(
  [string]$LogPath = "C:\App\Logs",
  [int]$Days = 7,
  [string]$Pattern = "ERROR",
  [string]$OutputPath = ".\error-report.csv"
)

$since = (Get-Date).AddDays(-$Days)

Get-ChildItem $LogPath -Filter *.log -File -Recurse |
  Where-Object { $_.LastWriteTime -ge $since } |
  Select-String -Pattern $Pattern |
  Select-Object Path, LineNumber, Line |
  Export-Csv $OutputPath -NoTypeInformation -Encoding UTF8

Write-Host "Exported: $OutputPath"

.\Export-ErrorReport.ps1 -LogPath C:\App\Logs -Days 14 -Pattern "ERROR|FATAL" -OutputPath .\errors.csv

$source = "C:\Work\Reports"
$dest = "C:\Work\Archive"
$limit = (Get-Date).AddDays(-90)

$targets = Get-ChildItem $source -Filter *.xlsx -File |
  Where-Object { $_.LastWriteTime -lt $limit }

$targets | Select-Object FullName, Length, LastWriteTime

if (-not (Test-Path $dest)) {
  New-Item -ItemType Directory -Path $dest
}

$targets |
  Select-Object FullName, Length, LastWriteTime |
  Export-Csv .\archive-targets.csv -NoTypeInformation -Encoding UTF8

$targets | Move-Item -Destination $dest -WhatIf

$targets | Move-Item -Destination $dest

Get-Command
Get-Help
Get-Member
Get-Location
Set-Location
Get-ChildItem
Get-Content
Select-String

Where-Object
Sort-Object
Select-Object
ForEach-Object
Format-Table
Format-List

Import-Csv
Export-Csv
ConvertFrom-Json
ConvertTo-Json
Set-Content
Add-Content
Out-File

New-Item
Copy-Item
Move-Item
Rename-Item
Remove-Item
Start-Service
Stop-Service
Restart-Service
Stop-Process

# 見る
Get-ChildItem .\logs -Filter *.tmp

# 削除予定を見る
Get-ChildItem .\logs -Filter *.tmp | Remove-Item -WhatIf

# 実行
Get-ChildItem .\logs -Filter *.tmp | Remove-Item

Get-Command で探す
Get-Help で使い方を見る
Get-Member でプロパティを確認する
Get-* で対象を見る
Where-Object で絞る
Select-Object で列を整える
Export-Csv で証跡を残す
-WhatIf で変更予定を確認する
最後に実行する

見る → 絞る → 記録する → 予行する → 実行する