Tee-Object

Syntax

Tee-Object
   [-InputObject <PSObject>]
   [-FilePath] <String>
   [-Append]
   [[-Encoding] <Encoding>]
   [<CommonParameters>]

Tee-Object
   [-InputObject <PSObject>]
   -LiteralPath <String>
   [[-Encoding] <Encoding>]
   [<CommonParameters>]

Tee-Object
   [-InputObject <PSObject>]
   -Variable <String>
   [<CommonParameters>]

Description

The Tee-Object cmdlet redirects output, that is, it sends the output of a command in two directions (like the letter T). It stores the output in a file or variable and also sends it down the pipeline. If Tee-Object is the last command in the pipeline, the command output is displayed at the prompt.

Examples

Example 1: Output processes to a file and to the console

This example gets a list of the processes running on the computer and sends the result to a file. Because a second path is not specified, the processes are also displayed in the console.

Get-Process | Tee-Object -FilePath "C:\Test1\testfile2.txt"

Handles  NPM(K)    PM(K)      WS(K) VM(M)   CPU(s)    Id ProcessName
-------  ------    -----      ----- -----   ------    -- -----------
83       4     2300       4520    39     0.30    4032 00THotkey
272      6     1400       3944    34     0.06    3088 alg
81       3      804       3284    21     2.45     148 ApntEx
81       4     2008       5808    38     0.75    3684 Apoint
...

Example 2: Output processes to a variable and `Select-Object`

This example gets a list of the processes running on the computer, saves them to the $proc variable, and pipes them to Select-Object.

Get-Process notepad | Tee-Object -Variable proc | Select-Object processname,handles

ProcessName                              Handles
-----------                              -------
notepad                                  43
notepad                                  37
notepad                                  38
notepad                                  38

The Select-Object cmdlet selects the ProcessName and Handles properties. Note that the $proc variable includes the default information returned by Get-Process.

Example 3: Output system files to two log files

This example saves a list of system files in a two log files, a cumulative file and a current file.

Get-ChildItem -Path D: -File -System -Recurse |
  Tee-Object -FilePath "c:\test\AllSystemFiles.txt" -Append |
    Out-File c:\test\NewSystemFiles.txt

The command uses the Get-ChildItem cmdlet to do a recursive search for system files on the D: drive. A pipeline operator (|) sends the list to Tee-Object, which appends the list to the AllSystemFiles.txt file and passes the list down the pipeline to the Out-File cmdlet, which saves the list in the NewSystemFiles.txt file.

Example 4: Print output to console and use in the pipeline

This example gets the files in a folder, prints them to the console, then filters the files for those that have a defined front matter metadata block. Finally, it lists the names of the articles that have front matter.

$consoleDevice = if ($IsWindows) {
    '\\.\CON'
} else {
    '/dev/tty'
}
$frontMatterPattern = '(?s)^---(?<FrontMatter>.+)---'

$articles = Get-ChildItem -Path .\reference\7.4\PSReadLine\About\ |
    Tee-Object -FilePath $consoleDevice |
    Where-Object {
        (Get-Content $_ -Raw) -match $frontMatterPattern
    }

$articles.Name

Directory: C:\code\docs\PowerShell-Docs\reference\7.4\PSReadLine\About

Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
-a---          12/13/2022 11:37 AM            384 .markdownlint.yaml
-a---           4/25/2023 11:28 AM          40194 about_PSReadLine_Functions.md
-a---           4/25/2023 10:58 AM          10064 about_PSReadLine.md

about_PSReadLine_Functions.md
about_PSReadLine.md

The example sets the $consoleDevice variable to the value of the current terminal's console device. On Windows, you can write to the current console device by redirecting your output to the \\.\CON filepath. On non-Windows systems, you use the /dev/tty filepath.

Then it sets the $frontMatterPattern variable to a regular expression that matches when a string starts with three dashes (---) and has any content before another three dashes. When this pattern matches an article's content, the article has a defined front matter metadata block.

Next, the example uses Get-ChildItem to retrieve every file in the About folder. Tee-Object prints the piped results to the console using the FileName parameter. Where-Object filters the files by getting their content as a single string with the Raw parameter of Get-Content and comparing that string to $frontMatterPattern.

Finally, the example prints the names of the files in the folder that have a defined front matter metadata block.

Parameters

-Append

-Encoding

-FilePath

-InputObject

-LiteralPath

-Variable

Inputs

PSObject

You can pipe objects to this cmdlet.

Outputs

PSObject

This cmdlet returns the object that it redirects.

Notes

PowerShell includes the following aliases for Tee-Object:

• Windows:
  • tee

You can also use the Out-File cmdlet or the redirection operator, both of which save the output in a file but do not send it down the pipeline.

Beginning in PowerShell 6, Tee-Object uses BOM-less UTF-8 encoding when it writes to files. If you need a different encoding, use the Out-File cmdlet with the Encoding parameter.

Related Links

• Compare-Object
• ForEach-Object
• Group-Object
• Measure-Object
• New-Object
• Select-Object
• Sort-Object
• Where-Object
• about_Redirection