Powershell: Split file to parts by placeholders

I have file all.sql with following structure

--------------start of file1.sql--------------
...
...content of file1.sql...
...
--------------end of file1.sql--------------


--------------start of file2.sql--------------
...
...content of file2.sql...
...
--------------end of file2.sql--------------

and I need to split file all.sql to separate files file1.sql, file2.sql, etc
You can use following Powershell script to do it

$workingDir="c:\[path_to_dir_with_files]\"
$allFileName="all.sql"

$pattern=[regex]'(?sm)--------------start of (.*?)--------------(.*?)--------------end of (.*?)--------------'

$file = Get-content $workingDir$allFileName -Raw 
foreach($match in $pattern.Matches($file)) {
  $outputFileName = $workingDir+$match.Groups[1].value
  Write-Output $outputFileName
  Set-Content -Path $outputFileName -Value $match.Groups[2].value
}

change pattern expression to hit your placeholders.