Powershell - Loop run console app >Wait for Ctrl+c - powershell

Question

I have a windows console app that currently runs to process some files, at the end of the run, if successful, it starts a windows service and I get the output > xxx service is now running, press control_c to exit.
The console app looks at a config file to pull some parameters, I need to be able to re-run this multiple times while changing the parameters in the config file first. To do this manually I'd do the following:
change config file
run the app from powershell
wait for the message above to appear
click ctrl + c to terminate
change config file and run again
I thought it makes sense to automate this in a PS script where I can just pass the config values for all the runs, then the script loops through the values, edit the config file and run the exe.
Issue I have is the loop gets "stuck" at first run because the application is waiting for the ctrl+c command so never progresses through the loop.
what I have at the moment looks like this:
foreach ($dt in $datesarr)
{
##edit config values with stuff in $dt
$output=(<path to app here>)
while ($output[-1] -notlike "*Control-C*")
{
Start-Sleep -Seconds 10
}
}
problem I have is the script never reaches the while loop as it's just stuck after running the app awaiting for ctrl + c... What I want it to do is launch the app, wait for it to get to the ctrl + c bit then exit the loop and pick the second value in the parameter.
Any thoughts would be hugely appreciated!

Answer 1

Try the following approach, which is based on direct use of the following, closely related .NET APIs:
System.Diagnostics.ProcessStartInfo
System.Diagnostics.Process
Instead of trying to programmatically press Ctrl-C, the process associated with the external program is simply killed (terminated).
# Remove the next line if you don't want to see verbose output.
$VerbosePreference = 'Continue'
$psi = [System.Diagnostics.ProcessStartInfo] #{
UseShellExecute = $false
WindowStyle = 'Hidden'
FileName = '<path to app here>'
Arguments = '<arguments string here>' # only if args must be passed
RedirectStandardOutput = $true
RedirectStandardError = $true # optional - if you also want to examine stderr
}
Write-Verbose "Launching $($psi.FileName)..."
$ps = [System.Diagnostics.Process]::Start($psi)
Write-Verbose "Waiting for launched process $($ps.Id) to output the line of interest..."
$found = $false
while (
-not $ps.HasExited -and
-not ($found = ($line = $ps.StandardOutput.ReadLine()) -match 'Control-C')
) {
Write-Verbose "Stdout line received: $line"
}
if ($found) {
Write-Verbose "Line of interest received; terminating process $($ps.Id)."
# Note: If the process has already terminated, this will be a no-op.
# .Kill() kills only the target process itself.
# In .NET Core / .NET 5+, you can use .Kill($true) to also
# kill descendants of the process, i.e. all processes launched
# by it, directly and via its children.
$ps.Kill()
} else {
Write-Error "Process $($ps.Id) terminated before producing the expected output."
}
$ps.Dispose()