Powershell: String concatenation with underscore confusion

In putting together a simple powershell script to download a file and store it on a filesystem, I came across some strangeness with the user of Underscore (_) when concatenation variables. Essentially, I wanted to create a filename based upon 2 powershell variables, separated by an underscore.

I wanted my filename to be: 

Richard_Brown.txt

And my powershell read something like:

$File = "C:\$FirstName_$LastName"

Interestingly, when run in my script the output of $File would be 

C:\Brown.txt

I was suspicious of the underscore and sure enough this was the causing the issue. I stumbled upon this thread on Stackoverflow which explains the issue as the underscore is a valid character in identifiers so its looking for a variable named $FirstName_.

There are 2 workarounds for this:

1) $File = "C:\$FirstName`_$LastName"

2) $File = "C:\${FirstName}_$LastName"

Powershell: Out-File truncate text

I was looking to use Powershell to write out some data from a SQL table using a combination of Invoke-Sqlcmd with out-file. Everything was going nicely until my output file suddenly started having data truncated. Something like:

Invoke-Sqlcmd -Query "SELECT LongText FROM MyTable" -ServerInstance $sql | out-file -filepath $filepath

Produced a file containing:

LongText
----------------
This was my really really long and boring piece of text that I had writ...

The thing is, it happened quite randomly. Or so I thought. Turns out that the out-file cmdlet outputs exactly as if it was appearing within the console on that machine and my console was too narrow for the text. (This is all in the documentation to be fair). So manipulating the size of your console window (by editing the properties) results in different output lengths.

However, each powrshell install on a machine can be different so I really need my script to be able to handle this limitation. As of writing, I couldn't find anything fullproof and my best hack was to just explicity set a width that I "knew" was big enough to cater for my text.

Invoke-Sqlcmd -Query "SELECT LongText FROM MyTable" -ServerInstance $sql | out-file -filepath $filepath -width 2000