Concatenating variables to pass to exe in powershell - powershell

Question

I'm writing a powershell script which calls an exe using the input parameters. This is my code:
param([string]$sourceIP, [string]$destinationIP, [string]$prefix)
$ErrorActionPreference = "Stop"
try
{
Write-Host "Starting Copy of Keyspaces to Dev"
Write-Host "Copying One"
.\CopyDatabase.exe -s $sourceIP -o $($prefix)_one -d $destinationIP -n $($prefix)_one -c
Start-Sleep -s 2
Write-Host "Copying Two"
.\CopyDatabase.exe -s $sourceIP -o $($prefix)_two -d $destinationIP -n $($prefix)_two -c
Start-Sleep -s 2
Write-Host "Copying Three"
.\CopyDatabase.exe -s $sourceIP -o $($prefix)_three -d $destinationIP -n $($prefix)_three -c
Start-Sleep -s 2
Write-Host "Copying Four"
.\CopyDatabase.exe -s $sourceIP -o $($prefix)_four -d $destinationIP -n $($prefix)_four -c
Write-Host "Finished Backup"
}
catch
{
write-host "EXCEPTION:"
write-host "Exception Type: $($_.Exception.GetType().FullName)"
write-host "Exception Message: $($_.Exception.Message)"
exit -1
}
It's working as I expect, except that $($prefix)_keyspace gives me prefix _keyspace where I want prefix_keyspace. I'm sure I can write a function or make a new variable for each concatenation, but I'm wondering if there's a command I can use for this that'll save me from having to do that. Thanks!

Answer 1

Replace the try block with this:
try
{
Write-Host "Starting Copy of Keyspaces to Dev"
Write-Host "Copying One"
.\CopyDatabase.exe -s $sourceIP -o ${prefix}_one -d $destinationIP -n ${prefix}_one -c
Start-Sleep -s 2
Write-Host "Copying Two"
.\CopyDatabase.exe -s $sourceIP -o ${prefix}_two -d $destinationIP -n ${prefix}_two -c
Start-Sleep -s 2
Write-Host "Copying Three"
.\CopyDatabase.exe -s $sourceIP -o ${prefix}_three -d $destinationIP -n ${prefix}_three -c
Start-Sleep -s 2
Write-Host "Copying Four"
.\CopyDatabase.exe -s $sourceIP -o ${prefix}_four -d $destinationIP -n ${prefix}_four -c
Write-Host "Finished Backup"
}
This should do your work. Not tested.