I have a PowerShell 1.0 script to just open a bunch of applications. The first is a virtual machine and the others are development applications. I want the virtual machine to finish booting before the rest of the applications are opened.
In bash I could just say "cmd1 && cmd2"
This is what I've got...
C:\Applications\VirtualBox\vboxmanage startvm superdooper
&"C:\Applications\NetBeans 6.5\bin\netbeans.exe"
Normally, for internal commands PowerShell does wait before starting the next command. One exception to this rule is external Windows subsystem based EXE. The first trick is to pipeline to Out-Null like so:
Notepad.exe | Out-Null
PowerShell will wait until the Notepad.exe process has been exited before continuing. That is nifty but kind of subtle to pick up from reading the code. You can also use Start-Process with the -Wait parameter:
Start-Process <path to exe> -NoNewWindow -Wait
If you are using the PowerShell Community Extensions version it is:
$proc = Start-Process <path to exe> -NoNewWindow -PassThru
$proc.WaitForExit()
Another option in PowerShell 2.0 is to use a background job:
$job = Start-Job { invoke command here }
Wait-Job $job
Receive-Job $job
Besides using Start-Process -Wait, piping the output of an executable will make Powershell wait. Depending on the need, I will typically pipe to Out-Null, Out-Default, Out-String or Out-String -Stream. Here is a long list of some other output options.
# Saving output as a string to a variable.
$output = ping.exe example.com | Out-String
# Filtering the output.
ping stackoverflow.com | where { $_ -match '^reply' }
# Using Start-Process affords the most control.
Start-Process -Wait SomeExecutable.com
I do miss the CMD/Bash style operators that you referenced (&, &&, ||). It seems we have to be more verbose with Powershell.
Just use "Wait-process" :
"notepad","calc","wmplayer" | ForEach-Object {Start-Process $_} | Wait-Process ;dir
job is done
If you use Start-Process <path to exe> -NoNewWindow -Wait
You can also use the -PassThru option to echo output.
Some programs can't process output stream very well, using pipe to Out-Null may not block it.
And Start-Process needs the -ArgumentList switch to pass arguments, not so convenient.
There is also another approach.
$exitCode = [Diagnostics.Process]::Start(<process>,<arguments>).WaitForExit(<timeout>)
Including the option -NoNewWindow gives me an error: Start-Process : This command cannot be executed due to the error: Access is denied.
The only way I could get it to work was to call:
Start-Process <path to exe> -Wait
Building upon @Justin & @Nathan Hartley 's answers:
& "my.exe" | Out-Null #go nowhere
& "my.exe" | Out-Default # go to default destination (e.g. console)
& "my.exe" | Out-String # return a string
the piping will return it in real-time
& "my.exe" | %{
if ($_ -match 'OK')
{ Write-Host $_ -f Green }
else if ($_ -match 'FAIL|ERROR')
{ Write-Host $_ -f Red }
else
{ Write-Host $_ }
}
Note: If the executed program returns anything other than a 0 exitcode, the piping will not work. You can force it to pipe with redirection operators such as 2>&1
& "my.exe" 2>&1 | Out-String
sources:
The question was asked long ago, but since answers here are kind of references, I may mention an up to date usage. With the current implementation of PowerShell (it's 7.2 LTS as of writing) you can use && as you would do in Bash.
Conditionally execute the right-hand side pipeline based on the success of the left-hand side pipeline.
# If Get-Process successfully finds a process called notepad, # Stop-Process -Name notepad is called Get-Process notepad && Stop-Process -Name notepad
Further info on documentation
Taking it further you could even parse on the fly
e.g.
& "my.exe" | %{
if ($_ -match 'OK')
{ Write-Host $_ -f Green }
else if ($_ -match 'FAIL|ERROR')
{ Write-Host $_ -f Red }
else
{ Write-Host $_ }
}
I guess we all don't remember ; is the simplest way to make a script wait for the previous command, the old DOS ';'. I use this ALLOT to convert long scripts to run in a remote session with enter-pssession, because Microsoft decided to make remote PowerShell session awkwardly restricted. I've written allot of scripts to run in TaskMgr and that can be quite a process to develop, so I use -command 'command to run;then another;then another', and so on.
I remember the wonderfully useful 'Call' command in DOS batch file scripting, and it looks like what 'wait-process' does, but not quite, as that specifically waits for a denoted process, not for the line above, which is what was originally asked all those years ago (what an old still-open thread!).
So here is a reminder (update) that the newer versions of PowerShell (not PS 1, good God don't use THAT!) has allot of (new) options for stopping inside, not exiting, the console, like 'exit' does, as some thought the original question was (you can simply 'break' to stop at that point...
But Break isn't what was asked, right prior answers before mselmany (https://stackoverflow.com/users/15224124/mselmany)?
So the answer to the question How to to use a single script to run and then wait for the next command is to use
&& or ; or |out-null or even |$null
Note: If you ever need to look something up use get-help, or find-command. That's why you have to regularly update your help files -see command below
#Update-Windows_Powerhell.ps1
$modules = $null
$modules = (Get-Module -ListAvailable).name
foreach ($module in $modules) {
Write-Output $module
Import-Module $module -NoClobber -Verbose -ErrorAction SilentlyContinue;
if((Get-Module -ListAvailable $module).Version -lt (Get-Module $module).Version){
Update-Help -Module $module -Confirm:$false
}
}
**you can change 'listAvailable' to find a speciifc module like '-ListAvailable Graph For more, that update regularly now, look at my Tech Blog: Click www.Burwell.tech!
