about_Output_Streams
Short description
Explains the availability and purpose of output streams in PowerShell.
Long description
PowerShell provides multiple output streams. The streams provide channels for different types of messages. You can write to these streams using the associated cmdlet or redirection. For more information, see about_Redirection.
PowerShell supports the following output streams.
| Stream # | Description | Introduced in | Write Cmdlet |
|---|---|---|---|
| 1 | Success stream | PowerShell 2.0 | Write-Output |
| 2 | Error stream | PowerShell 2.0 | Write-Error |
| 3 | Warning stream | PowerShell 2.0 | Write-Warning |
| 4 | Verbose stream | PowerShell 2.0 | Write-Verbose |
| 5 | Debug stream | PowerShell 2.0 | Write-Debug |
| 6 | Information stream | PowerShell 5.0 | Write-Information |
| n/a | Progress stream | PowerShell 2.0 | Write-Progress |
Note
The Progress stream doesn't support redirection.
Success stream
The Success stream is the default stream for normal, successful results.
Use the Write-Output cmdlet to explicitly write objects to this stream. This
stream is used for passing objects through the PowerShell pipeline. The
Success stream is connected to the stdout stream for native
applications.
Error stream
The Error stream is the default stream for error results. Use the
Write-Error cmdlet to explicitly write to this stream. The Error stream
is connected to the stderr stream for native applications. Under most
conditions, these errors can terminate the execution pipeline. Errors written
to this stream are also added to the $Error automatic variable. For more
information, see about_Automatic_Variables.
Warning stream
The Warning stream is intended for error conditions that are less severe
than errors written to the Error stream. Under normal conditions, these
warnings don't terminate execution. Warnings aren't written to the $Error
automatic variable. Use the Write-Warning cmdlet to explicitly write to this
stream.
Verbose stream
The Verbose stream is intended for messages that help users troubleshoot
commands as they're run interactively or from a script. Use the Write-Verbose
cmdlet to explicitly write messages to this stream. Many cmdlets provide
verbose output that's useful for understanding the internal workings of the
cmdlet. The verbose messages are output only when you use the -Verbose common
parameter. For more information, see about_CommonParameters.
Debug stream
The Debug stream is used for messages that help scripters understand why
their code is failing. Use the Write-Debug cmdlet to explicitly write to this
stream. The debug messages are output only when you use the -Debug common
parameter. For more information, see about_CommonParameters.
Debug messages are intended for script and cmdlet developers more than end users. These debug messages can contain internal details necessary for deep troubleshooting.
Information stream
The Information stream is intended to provide messages that help a user
understand what a script is doing. It can also be used by developers as an
additional stream used to pass information through PowerShell. The developer
can tag stream data and have specific handling for that stream. Use the
Write-Information cmdlet to explicitly write to this stream.
Write-Host also writes to the Information stream. The difference between
the cmdlets is that Write-Host also writes to the host console unless you
redirect the Information stream. Write-Information only writes to the
Information stream.
Progress stream
The Progress stream is used for messages that communicate progress in
longer running commands and scripts. Use the Write-Progress cmdlet to
explicitly write messages to this stream. The Progress stream doesn't
support redirection.
