Powershell Script to split one big file into multiple files with two pairs of a tag each in a file with a naming convention on filename

Question

I am writing a Powershell script to split one big file into multiple files with two pairs of a tag each in a file and those small filenames must follow a naming convention.

Example abcdef123.xml contents:

<parent>
    <child>
        <code1><code1>
        <text1><text1>
    </child>
    <child1>
        <code2><code2>
        <text2><text2>
    </child1>
    <child>
        <code3><code3>
        <text3><text3>
    </child>
    <child1>
        <code4><code4>
        <text4><text4>
    </child1>
    <child>
        <code5><code5>
        <text5><text5>
    </child>
    <child1>
        <code6><code6>
        <text6><text6>
    </child1>
    <child>
        <code7><code7>
        <text7><text7>
    </child>
    <child1>
        <code8><code8>
        <text8><text8>
    </child1>
</parent>

The Powershell script should split this big file into multiple files (with 2 pairs of <child> & <child1> each in the file) having the following criteria and take user input for file name convention (the date with miliseconds can remain same in all file name but variable j should change):-

Criteria:-

1. Add header <parent> and tail </parent> to each file.
2. File name should be in the format of UserinputstringMMDDYYYYHHMMSSMIL_n increment.xml (where MIL is milliseconds and n increment will be like 001, 002, 003, ...)
3. No two files should have the same filename.

Example file splits:-

file 1; stack_10132020134434789_001.xml contents:

<parent>
    <child>
        <code1><code1>
        <text1><text1>
    </child>
    <child1>
        <code2><code2>
        <text2><text2>
    </child1>
    <child>
        <code3><code3>
        <text3><text3>
    </child>
    <child1>
        <code4><code4>
        <text4><text4>
    </child1>
</parent>

file 2; stack_10132020134434791_002.xml contents:

<parent>
    <child>
        <code5><code5>
        <text5><text5>
    </child>
    <child1>
        <code6><code6>
        <text6><text6>
    </child1>
    <child>
        <code7><code7>
        <text7><text7>
    </child>
    <child1>
        <code8><code8>
        <text8><text8>
    </child1>
</parent>

Script I was trying:

csplit -ksf part. src.xml

n=000

#E.g. Enter beginning of file name :
#User entered-> stack
#read userinput

j=n+1

$date= date +%m%d%Y%H%M%S%3N

filename=$userinput$date_$j.xml

Answer 1

The following assumes that your XML file can be read in full and parsed into an XML DOM using the [xml] type (System.Xml.XmlDocument).

# Simulate parsing the input XML file.
# In your real code, you'd so something like:
#  [xml] $doc = (Get-Content -Raw some.xml)
# The XML here is a condensed and corrected version of the sample XML in your question.
[xml] $doc = @'
<parent><child><code1></code1><text1></text1></child><child1><code2></code2><text2></text2></child1><child><code3></code3><text3></text3></child><child1><code4></code4><text4></text4></child1><child><code5></code5><text5></text5></child><child1><code6></code6><text6></text6></child1><child><code7></code7><text7></text7></child><child1><code8></code8><text8></text8></child1></parent>
'@

# Create the template for the output file names, to be instantiated
# (again) later with the -f operator.
$userInputString = 'stack'  # use Read-Host to prompt the user for this string.
$fileNameTemplate = '{0}_{1}_{{0:000}}.xml' -f $userInputString, (Get-Date -Format 'MMddyyyyhhmmssfff')

# Create an auxiliary document for creating the output files.
$auxDoc = [xml] '<parent/>'

$batchSize = 4  # Count of child elements per output file.
$fileNum = 1; $offset = 0 # Initialize loop variables.
$children = $doc.parent.ChildNodes # Get all child elements of <parent>
# Loop in batches of $batchSize until all children have been processed.
while ($offset -lt $children.Count) {

  # Make the next $batchSize child elements the content of the aux. document...
  $auxDoc.DocumentElement.InnerXml = -join $(
   foreach ($c in $children[$offset..($offset+$batchSize-1)]) { $c.OuterXml }
  )

  # ... determine the output file name via the current sequence number...
  $fileName = $fileNameTemplate -f $fileNum

  # ...and save.
  # Note: Always use a *full* (absolute) path when calling .NET methods, because
  #       .NET's working dir. differs from PowerShell's.
  $auxDoc.Save("$PWD/$fileName")

  # Prepare for next iteration.
  $offset += $batchSize
  ++$fileNum

}