Powershell gotchas: standard out breaks lines to fit console

May 14, 2012


When Powershell writes to standard out, and there is now redirection in the Powershell script itself, it will assume that it writes to a console. Because of this, it kindly breaks lines if they are longer than 80 characters. So, given the following powershell file (.ps1):

# line-gunk.ps1

If you run this Powershell file from the Windows command line, and redirects output to a file:

C:>@powershell -file .line-gunk.ps1 > foo.txt

Then you will get:


However, if you do the redirection in Powershell, it’s fine:

PS C:> .line-gunk.ps1 > bar.txt

A näive fix to this, would be to change your script to use Write-Host to explicity write the text to the console. However, I consider this a bad practice because it would restrict the usage of your script as you could not manipulate the output further if reusing the script. I found this entry on stackoverflow which provides a better solution. Going back to the original script, here is a fixed one that worked for me:

# line-gunk-fixed.ps1
$Host.UI.RawUI.BufferSize = New-Object Management.Automation.Host.Size(500, 25)

Notice that I used the simplifed version from the stackoverflow entry, which might not work in all circumstances.


How did I come across this problem? I running Powershell build scripts in TeamCity and I was trying to report the build progress back to TeamCity. However, it somehow did not work. I then discovered that the status messages written by my script were broken by the line breaks, rendering them useless…

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Written by Vidar Kongsli who is a software professional living in Oslo, Norway. Works as a consultant, system architect and developer at Bredvid. You should follow him on Twitter