Renaming a file name to exclude the first couple parts Powershell - powershell

Question

I have over a million files like such: First_Last_MI_DOB_ and lots more information. Is there a way I can run a rename script that can remove just the first, last, Mi, and DOB from the file name, but keep the stuff after that? Thank you.

Answer 1

Edited from my answer to this question: Parse and Switch Elements of Folder Names using Powershell
# Path to folder
$Path = '.\'
# Regex to match "ID_000000..."
$Regex = 'ID_\d+.*$'
# Get all objects in path
Get-ChildItem -Path $Path |
# Select only objects that are not directory and name matches regex
Where-Object {!$_.PSIsContainer -and $_.Name -match $Regex} |
# For each such object
ForEach-Object {
# Rename object
Rename-Item -Path $_.FullName -NewName $Matches[0]
}
UPDATE #1 : It seems that you need to write a regex that will match a required part of the name and then use it in to rename a document.
Assuming that file name is x-John_Doe_._DOB_01-11-1990_M_ID_000000_TitleofDocument_DateofDocument_Docpagenu‌​mber_, here is couple of the examples:
Regex (https://regex101.com/r/gI0fZ2/2): (ID_\d+.*)$ - will match ID_{ONE_OR_MORE_DIGITS}{ANY_CHARACTERS}
Result:ID_000000_TitleofDocument_DateofDocument_Docpagenu‌​mber_
Regex (https://regex101.com/r/gI0fZ2/1): \d{4}_(M|F)_(.*)$ - will match {4_DIGITS}_M_{or}_F_ and capture everything after that in capture group.
Result:
1st match - M
2nd match (the one to use) - ID_000000_TitleofDocument_DateofDocument_Docpagenu‌​mber_
UPDATE #2:
All the names in each file are different, a long with different ID's.
For example: John_Doe_DOB_01/01/01_ID_000000 and the next file name
could be: John_Smith_DOB_01/02/01_ID_100000 and so on. I am thinking I
would just want to read the file name in as a string, split it by _
and then make the new file name the stuff from [4] and after. Is there
a way to do that?
Sure, you can do that, but I'd recommend a regex approach, because it would work for every filename that has ID_0xxxx string, no matter of what. I've modified my initial example with first regex, so it should work for you.
But if you'd like to try splitting approach, here is how to do it:
# Path to folder
$Path = '.\'
# Filename separator
$Separator = '_'
# Get all objects in path
Get-ChildItem -Path $Path |
# Select only objects that are not directory and name matches regex
Where-Object {!$_.PSIsContainer} |
# For each such object
ForEach-Object {
# Generate new name
$NewName = ($_.Name -split $Separator | Select-Object -Skip 4) -join $Separator
# Rename object
Rename-Item -Path $_.FullName -NewName $NewName
}