PowerShell to slip a text file on specific string - regex

Question

I am trying to split a large text file into several files based on a specific string. Every time I see the string ABCDE - 3 I want to cut and paste the content up to that string in a new text file. I also want to extract the last 4 of the social, last name and first name. The new text file needs be saved as first_name,last_name and last 4 of social.
See text file example and a bit of initial code. I would feel much more comfortbale doing it in Python but PowerShell is the only option.
$my_text = Get-Content .\ab.txt
$ssn_pattern = '([0-8]\d{2})-(\d{2})-(\d{4})'
ForEach ($file in my_text)

Answer 1

To get the firstname, lastname and the last 4 digits of the social, you could make use of capturing groups and use those groups when assembling the filename.
From your pattern, only the last 4 digits should be grouped.
You could use a pattern to start the match with TO: and from the next line get the values for the names and the number.
Then match all lines the do not start with ABCDE - 3 using a negative lookahead (?!
You can adjust the pattern and the code to match your exact text.
(?m)^[^\S\r\n]+TO:.*\r?\n\s*ATTN:\s*[A-Z]{3} ([^,\r\n]+),[^\S\r\n]*(.+?)[^\S\r\n]*[0-8]\d{2}-\d{2}-(\d{4})(?:\r?\n(?![^\S\r\n]+ABCDE - 3).*)*\r?\n[^\S\r\n]+ABCDE - 3.*
Regex demo
I constructed a code snippet using stackoverflow postings, so this might be improved. It basically comes down to load a raw string and get all the matches.
Then loop over all the matches and get the groups to assemble a filename an save the full match as the content.
If there are names which contain spaces and you don't want those to be in the filename, you could replace those with an empty string.
Example code:
$my_text = Get-Content -Raw ./Documents/stack-overflow/powershell/ab.txt
$pattern = "(?m)^[^\S\r\n]+TO:.*\r?\n\s*ATTN:\s*[A-Z]{3} ([^,\r\n]+),[^\S\r\n]*(.+?)[^\S\r\n]*[0-8]\d{2}-\d{2}-(\d{4})(?:\r?\n(?![^\S\r\n]+ABCDE - 3).*)*\r?\n[^\S\r\n]+ABCDE - 3.*"
Select-String $pattern -input $my_text -AllMatches |
ForEach-Object { $_.Matches } |
ForEach-Object {
$fileName = -join ($_.groups[2].Value, $_.groups[1].Value, $_.groups[3].Value)
Write-Host $fileName
Set-Content -Path "your-path-here/$fileName.txt" -Value $_.Value
}
When I run this, I get 2 files with the content for each match:
MIOTTISAREMO2222.txt
MIOTTSANREMO1111.txt