Adding a newline (line break) to a Powershell script - powershell

Question

I have a script I am running in Powershell, and I want to be able to put a line in my resulting text file output between the ccript name and the script content itself.
Currently, from the below, the line $str_msg = $file,[System.IO.File]::ReadAllText($file.FullName) is what I need, but I need a line to separate $file and the result of the next expression. How can I do this?
foreach ($file in [System.IO.Directory]::GetFiles($sqldir,"*.sql",
[System.IO.SearchOption]::AllDirectories))
{
$file = [System.IO.FileInfo]::new($file);
$Log.SetLogDir("");
$str_msg = $file,[System.IO.File]::ReadAllText($file.FullName);
$Log.AddMsg($str_msg);
Write-Output $str_msg;
# ...
}

Answer 1

$str_msg = $file,[System.IO.File]::ReadAllText($file.FullName) doesn't create a string, it creates a 2-element array ([object[]]), composed of the $file [System.IO.FileInfo] instance, and the string with the contents of that file.
Presumably, the .AddMsg() method expects a single string, so PowerShell stringifies the array in order to convert it to a single string; PowerShell stringifies an array by concatenating the elements with a single space as the separator by default; e.g.:
[string] (1, 2) yields '1 2'.
Therefore, it's best to compose $str_msg as a string to begin with, with an explicit newline as the separator, e.g.:
$strMsg = "$file`r`n$([System.IO.File]::ReadAllText($file.FullName))"
Note the use of escape sequence "`r`n" to produce a CRLF, the Windows-specific newline sequence; on Unix-like platforms, you'd use just "`n" (LF).
.NET offers a cross-platform abstraction, [Environment]::NewLine, which returns the platform-appropriate newline sequence (which you could alternatively embed as $([Environment]::NewLine) inside "...").
An alternative to string interpolation is to use -f, the string-formatting operator, which is based on the .NET String.Format() method:
$strMsg = '{0}{1}{2}' -f $file,
[Environment]::NewLine,
[System.IO.File]::ReadAllText($file.FullName)

Answer 2

Backtick-r+backtick-n will do a carriage return with a new line in PS. You could do a Get-Content of your $file variable as a new array variable, and insert the carriage return at a particular index:
Example file: test123.txt
If the file contents were this:
line1
line2
line3
Store the contents in an array variable so you have indices
[Array]$fileContent = Get-Content C:\path\to\test123.txt
To add a carriage return between line2 and line3:
$fileContent2 = $fileContent[0..1] + "`r`n" + $fileContent[2]
Then output a new file:
$fileContent2 | Out-File -FilePath C:\path\to\newfile.txt

Answer 3

You need to use the carriage return powershell special character, which is "`r".
Use it like this to add a carriage return in your line :
$str_msg = $file,"`r",[System.IO.File]::ReadAllText($file.FullName);
Check this documentation to have more details on Poewershell special characters.