Set-Content appends a newline (line break, CRLF) a

问题:

My original config file (web1.config) has no extra line and when viewed in notepad (showing all characters) looks as:

 <?xml version="1.0"?>
<configuration>
  <system.web>
    <compilation debug="true" targetFramework="4.6" />
    <httpRuntime targetFramework="4.6" />
  </system.web>
  <appSettings>
    <add key="myConnectionString" value="server=localhost;database=myDb;uid=myUser;password=myPass;" />
  </appSettings>
</configuration>

Now, I need to apply the script to change my database name to something else which looks like:

 Move-Item "web1.config" "webtemp.config"
Get-Content "webtemp.config" | ForEach-Object {$_ -replace "database=myDb;", "database=newDb;"} |Set-Content "web1.config" -Force
Remove-Item "webtemp.config"
Write-Output('Settings Changed')

So, the new file (web1.config) generated looks as:

Notice the extra line added at the end of the file (which is completely not needed) I tried all other options such as: - using out-file api - using .net IO method System.IO.StreamWriter - using -nonewline flag (it converts all 10 lines into single line) - using different encoding options - tried replacing \r\n to \r (don't work as again set-content generates the crlf always)

I'm using PowerShell v5.1.

回答1:

tl;dr (PSv5+; see bottom for older versions):

(Get-Content "webtemp.config") -replace "database=myDb;", "database=newDb;" -join "`n" |
  Set-Content -NoNewline -Force "web1.config"

^{Note: Replace "`n" with "`r`n" if you want Windows-style CRLF line endings rather than Unix-style LF-only line endings (PowerShell and many utilities can handle both).}

---

In PSv5+, Set-Content supports the -NoNewline switch, which instructs Set-Content not to add a newline (line break) after each input object. The same applies analogously to the Add-Content and Out-File cmdlets.

In other words: Set-Content -NoNewline directly concatenates the string representations of all its input objects:

> 'one', 'two' | Set-Content -NoNewline tmp.txt; Get-Content tmp.txt
onetwo

If what you're passing to Set-Content -NoNewline is a single string that already has embedded newlines, you can use it as-is and get the desired result:

> "one`ntwo" | Set-Content -NoNewline tmp.txt; "$(Get-Content -Raw tmp.txt)?"
one
two?

Note that Get-Content -Raw reads the file as a whole, as-is (aside from character decoding) and the fact that the ? appears directly after two implies that the file has no trailing newline.

In your case, since you're processing input lines one by one (via Get-Content without -Raw) and therefore outputting an array of lines (strings), you must first join them with a newline as the separator - between lines only - and pass the result to Set-Content -NoNewline, as shown at the top; here's a simplified example:

> ('one', 'two') -join "`n" | Set-Content -NoNewline tmp.txt; "$(Get-Content -Raw tmp.txt)?"
one
two?

'one', 'two' is a two-element string array that is a stand-in for your line-by-line processing command.

Encoding note:

In Windows PowerShell, Set-Content produces "ANSI"-encoded files by default, based on your system's legacy, single-byte code page.
To control the encoding explicitly, use the -Encoding parameter.

---

In PSv4-, a solution that uses the .NET Framework is needed:

> [System.IO.File]::WriteAllText('tmp.txt', ('one', 'two') -join "`n"); "$(Get-Content -Raw tmp.txt)?"
one
two?

Note that [System.IO.File]::WriteAllText(), in the absence of an encoding argument, defaults to BOM-less UTF-8.
Pass the desired [System.Text.Encoding] encoding instance as the 3rd argument as needed.

回答2:

I never noticed this, so i did a quick search and found:

set-content adds newlines by default

The suggested solution is to encode your content to bytes and then use Set-Content with the -Encoding parameter.

Set-Content test.txt ([byte[]][char[]] "test") -Encoding Byte

I tested it myself so i can confirm that this works.