Redirection

  command >  filename      Redirect command output to a file (overwrite)

  command >> filename      APPEND into a file

  command 2> filename      Redirect Errors from operation to a file(overwrite)

  command 2>> filename     APPEND errors to a file

  command 2>&1         Add errors to results

  command 1>&2         Add results to errors

  command | command    This is the basic form of a powershell Pipeline

In powershell it is not possible to redirect the output of an entire session (so Powershell.exe .... >filename.txt won't work) however a very similar text output can be produced using the Start-Transcript cmdlet.

The text files produced by powershell are (by default) in Unicode, if you need a different encoding, use Out-File instead of the redirection operator.

Examples

PS C:\>Get-ChildItem c:\windows\system >> "c:\my logs\text1.txt"

PS C:\>Get-ChildItem c:\windows\system | Out-File text2.txt -encoding ASCII

PS C:\>Start-Transcript -path c:\docs\Text3.txt
       ...
PS C:\>Stop-Transcript

“Most variables can show either an upward trend or a downward trend, depending on the base year chosen” - Thomas Sowell

Related:
Tee-Object - Send input objects to two places
Start-Transcript - Start a transcript of a command shell session
Stop-Transcript - Stop the transcription process