I have this simple script that just gets path an verifies if it exists.
function getPaths(){
$pathFromCMS = Read-Host "Please set the path for the copy files"
$pathToCMS = Read-Host "Please set the path to your CMS application"
if ((Test-Path -Path $pathFromCMS ) -and (Test-Path -Path $pathToCMS )){
Return $True
}
else{
[System.Windows.MessageBox]::Show('You have provided wrong path!')
Return $False
}
}
do{}while (! (getPaths) -eq $True)
echo "Hello there"
The problem is with the MessageBox::Show function. It somehow makes the loop stop when entering wrong paths. When I change it just for Write-Host "You have provided wrong path!" everything works fine. Can someone explain why this happens pls ?
The [System.Windows.MessageBox]::Show method returns a value, and that breaks your loop condition. You can suppress the return value by piping to Out-Null:
[System.Windows.MessageBox]::Show('You have provided wrong path!') | Out-Null
A MessageBox can have different buttons on it (e.g. YES/NO) and so is shown synchronously to allow you to capture what the user clicks. For example:
$preference = [System.Windows.MessageBox]::Show('Do you like MessageBoxes?', "MessageBox Preference", [System.Windows.MessageBoxButton]::YesNo)
In your case, even if you only want 'OK', it is still a good idea for it to wait, since the user always needs to manually dismiss it, unlike the output from Write-Host.
It is because there is nothing in your do{} block to be executed while the condition is satisfied.
What you want is:
do{(getPaths)}while ((getPaths) -ne $True)
Related
I am having an issue with my If/Else statement where it will successfully prompt the user until either a "Y/y" or an "N/n" are entered and will store the proper response in the $input variable outside of the Do/Until loop but will execute the first block of code in the following If Statement whether $input is equal to "Y/y" or "N/n"
How can I make it so the If Statement will only execute when $input is equal to "Y/y" and otherwise if it's "N/n" just execute the empty else and move on to the next $program in $InstallList?
I've tried using an ElseIf and checking for "N/n" but it still only executes the first If Statement.
I've also put Write-Host for $input as a check after it leaves the Do/Until loop and it is the correct input but all falls apart when it moves on to executing the If/Else Statement.
Please help.
foreach($program in $InstallList){
if($program -notin $Installed){
$input = ""
do {
$input = Read-Host -Prompt "$($Program) is not installed would you like to install now? (y/n)"
}
until(($input -eq "y") -or ($input -eq "n"))
if($input -eq "y")
{
Write-ProgressHelper -Message "Installing $($Program)" -StepNumber ($stepCounter++)
Start-Sleep -Seconds 3
Start-Process $Software.$program -Wait
Write-Host "$($Software) installed`n"
}
else {}
else{}
}
Abraham Zinala correctly states that use of $input as a custom variable should be avoided, because it is an automatic variable whose value is managed by PowerShell itself, namely to reflect pipeline input.
It is unfortunate that PowerShell even lets you assign a value, which is a problem that affects other automatic variables too - see this answer.
Technically, as long as you stay within the same scope, you can get away with using $input for custom purposes - though it should still be avoided.
Since this constraint is fulfilled in your code, use of $input is not the source of your problem; there is no obvious problem with your code.
Here's version of your code that avoids use of $input and streamlines ensuring that the user input is valid via the -in operator:
foreach ($program in $InstallList) {
if ($program -notin $Installed) {
do {
$response = Read-Host -Prompt "$($Program) is not installed would you like to install now? (y/n)"
} until ($response -in 'y', 'n')
if ($response -eq 'y') {
'yes' # ... install
}
}
}
Like I said, this code works in PowerShell version 2, but not in PowerShell version 5.
function wait
{
$compte = 0
Write-Host "To continue installation and ignore configuration warnings type [y], type any key to abort"
While(-not $Host.UI.RawUI.KeyAvailable -and ($compte -le 20))
{
$compte++
Start-Sleep -s 1
}
if ($compte -ge 20)
{
Write-Host "Installation aborted..."
break
}
else
{
$key = $host.ui.rawui.readkey("NoEcho,IncludeKeyup")
}
if ($key.character -eq "y")
{Write-Host "Ignoring configuration warnings..."}
else
{Write-Host "Installation aborted..."
}}
The official documentation or Read-Host -? will tell that it's not possible to use Read-Host in that manner. There is no possible parameter to tell it to run with some kind of timeout.
But there are various other questions detailing how to do this in PowerShell (usually utilizing C#).
The idea seems to be to check whenever the user pressed a key using $Host.UI.RawUI.KeyAvailable and check that for the duration of your timeout.
A simple working example could be the following:
$secondsRunning = 0;
Write-Output "Press any key to abort the following wait time."
while( (-not $Host.UI.RawUI.KeyAvailable) -and ($secondsRunning -lt 5) ){
Write-Host ("Waiting for: " + (5-$secondsRunning))
Start-Sleep -Seconds 1
$secondsRunning++
}
You could use $host.UI.RawUI.ReadKey to get the key that was pressed. This solution probably would not be acceptable if you need more complex input than a simple button press. See also:
Windows PowerShell Tip of the Week - Pausing a Script Until the User Presses a Key
PowerTip: Use PowerShell to Wait for a Key Press (Hey, Scripting Guy!)
Seth, thank you for your solution. I expanded on the example you provided and wanted to give that back to the community.
The use case is a bit different here - I have a loop checking if an array of VMs can be migrated and if there are any failures to that check the operator can either remediate those until the checks clear or they can opt to "GO" and have those failing VMs excluded from the operation. If something other than GO is typed state remains within the loop.
One downside to this is if the operator inadvertently presses a key the script will be blocked by Read-Host and may not be immediately noticed. If that's a problem for anyone I'm sure they can hack around that ;-)
Write-Host "Verifying all VMs have RelocateVM_Task enabled..."
Do {
$vms_pivoting = $ph_vms | Where-Object{'RelocateVM_Task' -in $_.ExtensionData.DisabledMethod}
if ($vms_pivoting){
Write-Host -ForegroundColor:Red ("Some VMs in phase have method RelocateVM_Task disabled.")
$vms_pivoting | Select-Object Name, PowerState | Format-Table -AutoSize
Write-Host -ForegroundColor:Yellow "Waiting until this is resolved -or- type GO to continue without these VMs:" -NoNewline
$secs = 0
While ((-not $Host.UI.RawUI.KeyAvailable) -and ($secs -lt 15)){
Start-Sleep -Seconds 1
$secs++
}
if ($Host.UI.RawUI.KeyAvailable){
$input = Read-Host
Write-Host ""
if ($input -eq 'GO'){
Write-Host -ForegroundColor:Yellow "NOTICE: User prompted to continue migration without the blocked VM(s)"
Write-Host -ForegroundColor:Yellow "Removing the following VMs from the migration list"
$ph_vms = $ph_vms | ?{$_ -notin $vms_pivoting} | Sort-Object -Property Name
}
}
} else {
Write-Host -ForegroundColor:Green "Verified all VMs have RelocateVM_Task method enabled."
}
} Until(($vms_pivoting).Count -eq 0)
Also note that all this $Host.UI stuff doesn't work from the Powershell ISE.
To find out from within a script you could test for $Host.Name -eq "ConsoleHost". When true you can use the code from this topic. Otherwise you could use $Host.UI.PromptForChoice or any other way of showing a dialog box. With System.Windows.Forms.Timer you can then set a timer, and code to close the dialog box or form can be run when it expires.
Very new to coding in general, so I fear I am missing something completely obvious. I want my program to check for a file. If it is there, just continue the code. If it has not arrived, continue cheking for a given amount of time, or untill the file shows up. My loop works on its own, so when i only select the do-part in Powershell ISE, it works. But when i try running it inside the if statement, nothing happens. The loops doesnt begin.
$exists= Test-Path $resultFile
$a = 1
if ($exists -eq "False")
{
do
{
$a++
log "Now `$a is $a "
start-sleep -s ($a)
$exists= Test-Path $resultFile
write-host "exists = $exists"
}
while (($a -le 5) -and ($exists -ne "True"))
}
Another way of doing this is using a while loop:
$VerbosePreference = 'Continue'
$file = 'S:\myFile.txt'
$maxRetries = 5; $retryCount = 0; $completed = $false
while (-not $completed) {
if (Test-Path -LiteralPath $file) {
Write-Verbose "File '$file' found"
$completed = $true
# Do actions with your file here
}
else {
if ($retryCount -ge $maxRetries) {
throw "Failed finding the file within '$maxRetries' retries"
} else {
Write-Verbose "File not found, retrying in 5 seconds."
Start-Sleep '5'
$retryCount++
}
}
}
Some tips:
Try to avoid Write-Host as it kills puppies and the pipeline (Don Jones). Better would be, if it's meant for viewing the script's progress, to use Write-Verbose.
Try to be consistent in spacing. The longer and more complex your scripts become, the more difficult it will be to read and understand them. Especially when others need to help you. For this reason, proper spacing helps all of us.
Try to use Tab completion in the PowerShell ISE. When you type start and press the TAB-key, it will automatically propose the options available. When you select what you want with the arrow down/up and press enter, it will nicely format the CmdLet to Start-Sleep.
The most important tip of all: keep exploring! The more you try and play with PowerShell, the better you'll get at it.
As pointed out in comments, your problem is that you're comparing a boolean value with the string "False":
$exists -eq "False"
In PowerShell, comparison operators evaluate arguments from left-to-right, and the type of the left-hand argument determines the type of comparison being made.
Since the left-hand argument ($exists) has the type [bool] (a boolean value, it can be $true or $false), PowerShell tries to convert the right-hand argument to a [bool] as well.
PowerShell interprets any non-empty string as $true, so the statement:
$exists -eq "False"
is equivalent to
$exists -eq $true
Which is probably not what you intended.
Very new to coding in general, so I fear I am missing something completely obvious. I want my program to check for a file. If it is there, just continue the code. If it has not arrived, continue cheking for a given amount of time, or untill the file shows up. My loop works on its own, so when i only select the do-part in Powershell ISE, it works. But when i try running it inside the if statement, nothing happens. The loops doesnt begin.
$exists= Test-Path $resultFile
$a = 1
if ($exists -eq "False")
{
do
{
$a++
log "Now `$a is $a "
start-sleep -s ($a)
$exists= Test-Path $resultFile
write-host "exists = $exists"
}
while (($a -le 5) -and ($exists -ne "True"))
}
Another way of doing this is using a while loop:
$VerbosePreference = 'Continue'
$file = 'S:\myFile.txt'
$maxRetries = 5; $retryCount = 0; $completed = $false
while (-not $completed) {
if (Test-Path -LiteralPath $file) {
Write-Verbose "File '$file' found"
$completed = $true
# Do actions with your file here
}
else {
if ($retryCount -ge $maxRetries) {
throw "Failed finding the file within '$maxRetries' retries"
} else {
Write-Verbose "File not found, retrying in 5 seconds."
Start-Sleep '5'
$retryCount++
}
}
}
Some tips:
Try to avoid Write-Host as it kills puppies and the pipeline (Don Jones). Better would be, if it's meant for viewing the script's progress, to use Write-Verbose.
Try to be consistent in spacing. The longer and more complex your scripts become, the more difficult it will be to read and understand them. Especially when others need to help you. For this reason, proper spacing helps all of us.
Try to use Tab completion in the PowerShell ISE. When you type start and press the TAB-key, it will automatically propose the options available. When you select what you want with the arrow down/up and press enter, it will nicely format the CmdLet to Start-Sleep.
The most important tip of all: keep exploring! The more you try and play with PowerShell, the better you'll get at it.
As pointed out in comments, your problem is that you're comparing a boolean value with the string "False":
$exists -eq "False"
In PowerShell, comparison operators evaluate arguments from left-to-right, and the type of the left-hand argument determines the type of comparison being made.
Since the left-hand argument ($exists) has the type [bool] (a boolean value, it can be $true or $false), PowerShell tries to convert the right-hand argument to a [bool] as well.
PowerShell interprets any non-empty string as $true, so the statement:
$exists -eq "False"
is equivalent to
$exists -eq $true
Which is probably not what you intended.
I wasn't sure how to describe this problem in the title so here goes.
I call a function from a script in another script. In that function i have a while loop that basically keeps looping through a set of ip's and looks up their hostname. when the while loop times out or we have all the host names.
it returns the hostnames.
My problem is that the return value contains every single Write-Host i'm doing in that function.
i know it's because Write-Host puts stuff on the pipeline and the return just returns whatever it has.
How do i go about fixing this?
The entire script i run get's logged in a log file which is why i want to have some verbose logging.
| out-null on write-host fixes the issue but it doesn't print the write-host values in the script.
in main.psm1 i have a function like so:
$nodes = #("ip1", "ip2", "ip3", "ip4")
$nodesnames = DoStuff -nodes $nodes
then in functions.psm1 i have functions like:
Function DoStuff
{
param($nodes)
$timeout = 300
$timetaken = 0
$sleepseconds = 5
$nodenames = #("$env:COMPUTERNAME")
while(($nodenames.count -lt $nodes.count) -and ($timetaken -lt $timeout))
{
try
{
Write-Host "Stuff"
foreach($node in $nodes)
{
$nodename = SuperawesomeFunction $node
Write-Host "$nodename"
if($nodenames -notcontains $nodename)
{
$nodenames += #($nodename)
}
}
}
catch
{
Write-Host "DoStuff Failed because $_"
}
Start-Sleep $sleepseconds
$timetaken += $sleepseconds
}
return $nodenames
}
Function SuperawesomeFunction
{
param($node)
$nodename = [System.Net.Dns]::GetHostEntry("$node")
return $nodename
}
Thanks.
So the answer is, your function is working like it is by design. In PowerShell a function will return output in general to the pipeline, unless specifically directed otherwise.
You used Echo before, which is an alias of Write-Output, and output is passed down the pipe as I mentioned before. As such it would be collected along with the returned $nodenames array.
Replacing Echo with Write-Host changes everything because Write-Host specifically tells PowerShell to send the information to the host application (usually the PowerShell Console or PowerShell ISE).
How do you avoid this? You could add a parameter specifying a path for a logfile, and have your function update the logfile directly, and only output the relevant data.
Or you can make an object with a pair of properties that gets passed back down the pipe which has the DNS results in one property, and the errors in another.
You could use Write-Error in the function, and set it up as an advanced function to support -errorvariable and capture the errors in a separate variable. To be honest, I'm not sure how to do that, I've never done it, but I'm 90% sure that it can be done.