powershell-docs

Table of Contents

• General
  • DateTime Manipulation
    • Playing with Days
  • File Manipulation
    • Changing Extensions
    • Pin Pointing Information in a CSV
  • SSH & SCP Operations
    • Execute Commands Over SSH
    • Synchronize a Remote Directory to Local

General

DateTime Manipulation

Playing with Days

Getting the previous day's date, and putting it into ISO format.

$ "{0:yyyyMMdd}" -f (Get-Date).AddDays(-1)

Another method is by piping the values. In the following example I want to get the previous months abbreviated name.

$ (Get-Date).AddMonths(-1) | Get-Date -UFormat %b

File Manipulation

Changing Extensions

Change the extensions of all files within a folder.

$Global:path = "C:\Temp"
$Global:filesToChange = $(Get-ChildItem -Path "$Global:path\*.*" -Include *.txt)

ForEach($file in $Global:filesToChange) {
    $newFileName = $(Split-Path -Path $file -Leaf | % { $_.split(.)[0] } | % { "$_.csv" }
    Rename-Item -Path $file -NewName $newFileName
}

This can also be done recursively as per below:

$Global:path = "C:\Temp"
$Global:filesToChange = $(Get-ChildItem -Recurse -Path "$Global:path\" -Include *.txt)

ForEach($file in $Global:filesToChange) {
    $newFileName = $(Split-Path -Path $file -Leaf | % { $_.split(.)[0] } | % { "$_.csv" }
    Rename-Item -Path $file -NewName $newFileName
}

Pin Pointing Information in a CSV

This is about getting a value of a column using in essence x,y coordinates.

Here is an example CSV that we will use. This example will be looking at a backup schedule, and if a server should be backed up on a particular date or not.

serverName,20140826,20140827,20140828,20140829
myServer1,0,1,0,0
myServer2,1,0,1,0
myServer3,0,0,1,1

The above csv has the filename schedule.csv, and will be sitting in the same directory as the script.

$todaysDate = Get-Date -Format "yyyyMMdd"
$localMachine = $env:computername
$scheduleCsv = Import-Csv -Path "$PSScriptRoot\schedule.csv"

$returnValue = $scheduleCsv | ? { $_.serverName -eq $localMachine } | % { $_.$todaysDate }

if($returnValue -eq 1) {
    Write-Host ("{0} should backup today" -f $localMachine)
} else {
    Write-Warning ("{0} should not backup today" -f $localMachine)
}

SSH & SCP Operations

These operations all require WinSCP.net and the following import line. `Add-Type -Path "C:\WinSCP\WinSCPnet.dll"

Execute Command Over SSH

This can be used to execute a command on a remote server using SSH. Please keep in mind that in order to prefix variables with $Local: they must be declared inside of a function, otherwise omit the $Local:.

# -- Declare all the Session Options
$Local:sessionOptions = New-Object WinSCP.SessionOptions
$Local:sessionOptions.Protocol = [WinSCP.Protocol]::Sftp
$Local:sessionOptions.HostName = "server.example.com"
$Local:sessionOptions.UserName = "root"
  # -- Please see note below about the SshPrivateKeyPath
$Local:sessionOptions.SshPrivateKeyPath = "myPrivateKey"
$Local:sessionOptions.SshHostKeyFingerprint = "ssh-rsa 2048 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx"
$Local:sessionOptions.TimeoutInMilliseconds = "30000"

# -- Create the Session
$Local:session = New-Object WinSCP.Session

try
{
    # -- Initialize and Open the Session
    $Local:session.Open($Local:sessionOptions)
    
    # -- Build the command for execution
    $Local:command = "ls -l /bin"
    
    # -- Execute the Command
    $Local:session.ExecuteCommand($Local:command)
}
catch [Exception]
{
    Write-Error $_.Exception.Message
}
finally
{
    $Local:session.Dispose()
}

As per the above note about the SshPrivateKeyPath, with this you can either define the path to the key (where the key is not encrypted and does not require a password) or, if you just put the name of the key and nothing else, as long as the key is loaded in Pageant then it will use that keys. As such you will be able to have an encrypted SSH Private Key.

Synchronize a Remote Directory to Local

This will sync a directory from a remote server to a directory on our local machine, after the sync has completed it will also remove the file from the remote machine.

# -- Declare all the Session Options
$Local:sessionOptions = New-Object WinSCP.SessionOptions
$Local:sessionOptions.Protocol = [WinSCP.Protocol]::Sftp
$Local:sessionOptions.HostName = "server.example.com"
$Local:sessionOptions.UserName = "root"
$Local:sessionOptions.SshPrivateKeyPath = "myPrivateKey"
$Local:sessionOptions.SshHostKeyFingerprint = "ssh-rsa 2048 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx"
$Local:sessionOptions.TimeoutInMilliseconds = "30000"

# -- Create the Session
$Local:session = New-Object WinSCP.Session

try
{
    # -- Initialize and Open Session
    $Local:session.Open($Local:sessionOptions)
    
    # -- Set the Remote and Local Paths to Variables
    $Local:remotePath = "/home/documents"
    $Local:localPath = "C:\Users\myUser\Documents"
    
    # -- Synchronize Directories and Collect Results
    $Local:synchronizationResult = $Local:session.SychronizeDirectories(
        [WinSCP.SynchronizationMode]::Local, $Local:localPath, $Local:remotePath, $False)
    
    ForEach($Local:download in $Local:synchronizationResult.Downloads) {
        if($Local:download.Error -eq $Null) {
            Write-Host ("Download of {0} succeeded, removing from source" -f
                $Local:download.FileName)
            
            # -- Remove Remote File
            $Local:removalResult = $Local:session.RemoveFiles(
                $Local:session.EscapeFileMask($Local:download.FileName))
            
            if($Local:removalResult.IsSuccess) {
                Write-Host ("Removal of {0} succeeded." -f
                    $Local:download.FileName)
            } else {
                Write-Error ("Removal of {0} failed!" -f
                    $Local:download.FileName)
            }
        } else {
            Write-Error ("Download of {0} failed: {1}" -f
                $Local:download:FileName, $Local:download.Error.Message)
        }
    }
}
catch [Exception]
{
    Write-Error $_.Exception.Message
}
finally
{
    $Local:session.Dispose()
}