powershell - Writing console output to a file - file is unexpectedly empty

Question

I'm new to scripting and I am trying to write the information returned about a VM to a text file. My script looks like this:

Connect-VIServer -Server 192.168.255.255 -Protocol https -User xxxx -Password XXXXXX

Get-VM -Name xxxxxx 

Get-VM xxxxx | Get-HardDisk | Select Parent, Name, Filename, DiskType, Persistence | FT -AutoSize 

Out-File -FilePath C:Filepath

I am able to connect to the VM, retrieve the HDD info and see it in the console. The file is created where I want it and is correctly named. No data is ever put into the file. I have tried Tee-Object with the same results. I've also tried the -append switch. I did see a post about the data being returned as an array and Powershell is not able to move the data from an array to a string. Do I need to create a variable to hold the returned data and write to file from there?

Thanks

Answer 1

Guenther Schmitz' answer is effective, but it's worth explaining why:

• Your Out-File -FilePath C:Filepath is a stand-alone command that receives no input.

  • An Out-File call with no input simply creates an empty file (0 bytes).

• In order for cmdlets such as Out-File to receive input from (an)other command(s) (represented as ... below), you must use the pipeline, which means that you must place a | after the input command(s) and follow it with your Out-File call:
  ^{Note that I'm using the shorter -Path parameter alias for the less commonly used -FilePath[1]}

  ... | Out-File -Path C:Filepath
  

  • In the simplest case, as above, the entire command (pipeline) is placed on the same line; if you want to spread it across multiple lines for readability, you have have two choices:

    • Put a line break immediately after |, which tells PowerShell that the command continues on the next line:

      ... |
        Out-File -Path C:Filepath
      

    • End a line with an explicit line continuation, which means placing ` at the very end of a line:

      ... `
      | Out-File -Path C:Filepath
      

Alternatively, since you're using Out-File with its default behavior, you could use >, an output redirection, instead:

... > C:Filepath

---

A couple of asides:

• Using Out-File with something other than strings, and using Format-* cmdlets in general, means that the output is only suitable for display (human consumption), not for further programmatic processing.

• If you want to send output to both the console and a file, use the Tee-Object cmdlet, as TobyU suggests:

  ... | Tee-Object -Path C:Filepath
  

---

^{[1] Strictly speaking, -LiteralPath is the best choice in this case, because -Path interprets its arguments as wildcard expressions. However, omitting -Path, i.e. specifying the file path as a positional argument, as is common, implicitly binds to -Path.}