Writing console output to a file - file is unexpectedly empty

问题

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

回答1:

try this:

Get-VM xxxxx |
 Get-HardDisk |
   Select Parent, Name, Filename, DiskType, Persistence |
     Out-File -FilePath C:\Filepath

回答2:

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.}

来源：https://stackoverflow.com/questions/55101518/writing-console-output-to-a-file-file-is-unexpectedly-empty

标签

powershell

file-io

pipeline