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"
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
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.
Out-String changes the output to a single, multi-line string, whereas PowerShell by default returns an array of lines. Start-Process should be avoided for console applications (unless you truly want to run them in a new window) because you won't be able to capture or redirect their output. –
Redmond Just use "Wait-process" :
"notepad","calc","wmplayer" | ForEach-Object {Start-Process $_} | Wait-Process ;dir
job is done
-PassThru, otherwise it won't wait –
Frenchy If you use Start-Process <path to exe> -NoNewWindow -Wait
You can also use the -PassThru option to echo output.
-PassThru doesn't echo output (a non-console-application by definition won't produce console output), it outputs a System.Diagnostics.Process instance that represents the newly launched process, so you can examine its properties and wait for it to exit later. –
Redmond 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.
$exitCode = [Diagnostics.Process]::Start(<process>,<arguments>).WaitForExit(<timeout>)
Including the option -NoNewWindow gives me an error: Start-Process : This command cannot be executed due to the error: Access is denied.
The only way I could get it to work was to call:
Start-Process <path to exe> -Wait
The question was asked long ago, but since answers here are kind of references, I may mention an up to date usage. With the current implementation of PowerShell (it's 7.2 LTS as of writing) you can use && as you would do in Bash.
Conditionally execute the right-hand side pipeline based on the success of the left-hand side pipeline.
# If Get-Process successfully finds a process called notepad, # Stop-Process -Name notepad is called Get-Process notepad && Stop-Process -Name notepad
Further info on documentation
Building upon @Justin & @Nathan Hartley 's answers:
& "my.exe" | Out-Null #go nowhere
& "my.exe" | Out-Default # go to default destination (e.g. console)
& "my.exe" | Out-String # return a string
the piping will return it in real-time
& "my.exe" | %{
if ($_ -match 'OK')
{ Write-Host $_ -f Green }
else if ($_ -match 'FAIL|ERROR')
{ Write-Host $_ -f Red }
else
{ Write-Host $_ }
}
Note: If the executed program returns anything other than a 0 exitcode, the piping will not work. You can force it to pipe with redirection operators such as 2>&1
& "my.exe" 2>&1 | Out-String
sources:
Taking it further you could even parse on the fly
e.g.
& "my.exe" | %{
if ($_ -match 'OK')
{ Write-Host $_ -f Green }
else if ($_ -match 'FAIL|ERROR')
{ Write-Host $_ -f Red }
else
{ Write-Host $_ }
}
There's always cmd.
cmd /c start /wait notepad
Or
notepad | out-host
Here's another odd one. Start-process keeps waiting for notepad, even though the 2nd powershell exits. ("cmd /c start /wait powershell notepad" doesn't do this.) So even if anything in the process tree runs in the background (the NSIS uninstaller does this), it still waits.
start-process -wait powershell notepad
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-ArgumentList, separate them with commas like-ArgumentList /D=test,/S. – Treva