Set-Content using variables - powershell

Question

I'm trying to generate PowerShell scripts using a PowerShell script. How do I get the variables' values inside the content of the newly generated script?
foreach ($server in $testServers) {
New-Item -ItemType File -Name "$($server)_wu.ps1" -Path "D:\tools\windows updates\uscripts"
Set-Content -Path "D:\tools\windows updates\uscripts\$($server)_wu.ps1" -Value {
$computer = $server
Invoke-Command -ComputerName $computer -ScriptBlock {
Set-ExecutionPolicy Bypass
Find-Module PSWindowsUpdate | Install-Module -Force | Import-Module -Force
}
$updatesCount = (Get-WindowsUpdate -ComputerName $computer).Count
while ($updatesCount -gt "0") {
psexec \\$computer -s "powershell.exe "Install-WindowsUpdate -Confirm:`$false -IgnoreReboot""
Restart-Computer -ComputerName $computer -Force -Wait
$updatesCount = (Get-WindowsUpdate -ComputerName $computer).Count
}
}
}
The result here is the following:
$computer = $server
Invoke-Command -ComputerName $computer -ScriptBlock {
Set-ExecutionPolicy Bypass
Find-Module PSWindowsUpdate | Install-Module -Force | Import-Module -Force
}
$updatesCount = (Get-WindowsUpdate -ComputerName $computer).Count
while ($updatesCount -gt "0") {
psexec \\$computer -s "powershell.exe "Install-WindowsUpdate -Confirm:`$false -IgnoreReboot""
Restart-Computer -ComputerName $computer -Force -Wait
$updatesCount = (Get-WindowsUpdate -ComputerName $computer).Count
}
But, in the new script, I'd like to have $server replaced by the name of the server for which the script is generated.

Answer 1

Alright - so I couldn't figure out how to manipulate my string and ended up solving it like this... Any shorter, simpler answer is absolutely welcome (note that the rest of the script changed a bit as well)
foreach ($server in $testServers) {
New-Item -ItemType File -Name "$($server)_wu.ps1" -Path "\\VILV12ICTSCRIPT\d$\windowsupdates\uscripts"
$value = '
$computer = $PSCommandPath
$computer = $computer.Split("`\")[3]
$computer = $computer.Split("_")[0]
Invoke-Command -ComputerName $computer -ScriptBlock {
Set-ExecutionPolicy Bypass
Find-Module PSWindowsUpdate | Install-Module -Force | Import-Module -Force
}
$updatesCount = (PsExec.exe \\$computer -s "powershell.exe "Get-WindowsUpdate"").Count
while ($updatesCount -gt "0") {
psexec \\$computer -s "powershell.exe "Install-WindowsUpdate -Confirm:`$false -IgnoreReboot""
Restart-Computer -ComputerName $computer -Force -Wait
$updatesCount = (PsExec.exe \\$computer -s "powershell.exe "Get-WindowsUpdate"").Count
}
Write-Host "No more updates available for $($computer)" -BackgroundColor DarkGreen
'
Set-Content -Path "\\VILV12ICTSCRIPT\d$\windowsupdates\uscripts\$($server)_wu.ps1" -Value $value
}
And both the script to generate and the generated scripts work like charms (^^,)
Cheers

Answer 2

The canonical way to do what you're asking is probably to use a here-string and insert particular values via the format operator (-f):
foreach ($server in $testServers) {
#'
$computer = '{0}'
Invoke-Command -ComputerName $computer -ScriptBlock {
Set-ExecutionPolicy Bypass
Find-Module PSWindowsUpdate | Install-Module -Force | Import-Module -Force
}
$updatesCount = (Get-WindowsUpdate -ComputerName $computer).Count
while ($updatesCount -gt "0") {
psexec \\$computer -s 'powershell.exe "Install-WindowsUpdate -Confirm:$false -IgnoreReboot"'
Restart-Computer -ComputerName $computer -Force -Wait
$updatesCount = (Get-WindowsUpdate -ComputerName $computer).Count
}
'# -f $server | Set-Content -Path "D:\tools\windows updates\uscripts\${server}_wu.ps1"
}
However, I'd argue that writing one parameterized script and invoking that with the respective computer name might be a more appropriate solution than creating one script per computer:
[CmdletBinding()]
Param(
[Parameter(Mandatory=$true)]
[string]$Computer
)
Invoke-Command -ComputerName $Computer -ScriptBlock {
Set-ExecutionPolicy Bypass
Find-Module PSWindowsUpdate | Install-Module -Force | Import-Module -Force
}
$updatesCount = (Get-WindowsUpdate -ComputerName $Computer).Count
while ($updatesCount -gt "0") {
psexec \\$Computer -s 'powershell.exe "Install-WindowsUpdate -Confirm:$false -IgnoreReboot"'
Restart-Computer -ComputerName $Computer -Force -Wait
$updatesCount = (Get-WindowsUpdate -ComputerName $Computer).Count
}
Invocation:
PS> script.ps1 -Computer FOO