How to cat a UTF-8 (no BOM) file properly/globally in PowerShell? (to another file)

Question

Create a file utf8.txt. Ensure the encoding is UTF-8 (no BOM). Set its content to €

In cmd.exe:

type utf8.txt > out.txt

Content of out.txt is €

In PowerShell (v4):

cat .\utf8.txt > out.txt

or

type .\utf8.txt > out.txt

Out.txt content is €

How do I globally make PowerShell work correctly?

Tryma

Answer 1

Note: This answer is about Windows PowerShell (up to v5.1); PowerShell (Core) 7+, the cross-platform edition of PowerShell, now fortunately consistently defaults to BOM-less UTF-8 on both in- and output.

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Windows PowerShell, unlike the underlying .NET Framework^[1] , uses the following defaults:

• on input:^[2] files without a BOM (byte-order mark) are assumed to be in the system's default encoding, which is the legacy Windows code page ("ANSI" code page: the active, culture-specific single-byte encoding, as configured via Control Panel).

• on output: the > and >> redirection operators produce UTF-16 LE files by default (which do have - and need - a BOM).

File-consuming and -producing cmdlets do usually support an -Encoding parameter that lets you specify the encoding explicitly.
Prior to Windows PowerShell v5.1, using the underlying Out-File cmdlet explicitly was the only way to change the encoding.
In Windows PowerShell v5.1+, > and >> became effective aliases of Out-File, allowing you to change the encoding behavior of > and >> via the $PSDefaultParameterValues preference variable; e.g.:
$PSDefaultParameterValues['Out-File:Encoding'] = 'utf8'.

For Windows PowerShell to handle UTF-8 properly, you must specify it as both the input and output encoding^[3] , but note that on output, PowerShell invariably adds a BOM to UTF-8 files.

Applied to your example:

Get-Content -Encoding utf8 .\utf8.txt | Out-File -Encoding utf8 out.txt

To create a UTF-8 file without a BOM in PowerShell, see this answer.

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^{[1] .NET Framework uses (BOM-less) UTF-8 by default, both for in- and output.
This - intentional - difference in behavior between Windows PowerShell and the framework it is built on is unusual. The difference went away in PowerShell [Core] v6+: both .NET [Core] and PowerShell [Core] default to BOM-less UTF-8.}

^{[2] This applies to Get-Content and notably also to source code read by the PowerShell engine. Unfortunately, the default behavior varies across cmdlets; for instance, Import-Csv assumes UTF-8. For an overview of the default character encoding used by all built-in cmdlets in Windows PowerShell, see the bottom section of this answer.}

^{[3] Cmdlets such as Get-Content do, however, automatically recognize UTF-8 files with a BOM, and so does the PowerShell engine when reading source code.}

Skimmia

Answer 2

For PowerShell 5.1, enable this setting:

Control Panel, Region, Administrative, Change system locale, Use Unicode UTF-8 for worldwide language support

Then enter this into PowerShell:

$PSDefaultParameterValues['*:Encoding'] = 'Default'

Alternatively, you can upgrade to PowerShell 6 or higher.

https://github.com/PowerShell/PowerShell

Beefeater