Extract CN or directory path from DN

split-distinguishedName.ps1

# Classic edition v1
function Split-DistinguishedName {
	param (
		[alias('dn')][string]$distinguishedName,
		[alias('leaf')][switch]$cn,
		[alias('parent')][switch]$ou,
		[switch]$path
	)
	if (-not $distinguishedName) {return}
	$dnpart = $distinguishedName -split '(,DC=)|(,OU=)|(,CN=)',2
	if (-not $dnpart[1]) {return $distinguishedName}
	$dpath = '{0}{1}' -f $dnpart[1].Substring(1),$dnpart[2]
	if ($cn) {$dnpart[0] -replace 'CN='}
	elseif ($path) {$dpath}
	elseif ($ou) {
		$dpath = ($dpath -split '(,DC=)|(,OU=)|(,CN=)',2)[0]
		if ($dpath -match '^(CN|OU)=') {$dpath -replace 'CN=|OU='}
	}
	else {
		$dnpart[0] -replace 'CN='
		($dpath -split '(,DC=)|(,OU=)|(,CN=)',2)[0] -replace 'CN=|OU='
		$dpath
	}
} # END Split-DistinguishedName

# Regexp edition
function Split-DistinguishedName {
	param (
		[alias('dn')][string]$distinguishedName,
		[alias('leaf')][switch]$cn,
		[alias('parent')][switch]$ou,
		[switch]$path
	)
	if (-not $distinguishedName) {return}
	$rxOU   = '^(CN=(?<CN>.*?(?=,))?),(?<OUName>(OU|CN)=.*?(?=,))'
	$rxOU   = '^(CN=(?<CN>.*?(?=,))?)(,OU|,CN)=(?<OUName>.*?(?=,))' # trims OU=|CN=
	$rxPath = '^(CN=(?<CN>.*?(?=,))?),(?<Path>(OU=|CN=|DC=).+)'
	if ($cn) {
		if ($distinguishedName -match $rxPath) {$matches['CN']}
	}
	elseif ($path) {
		if ($distinguishedName -match $rxPath) {$matches['Path']}
	}
	elseif ($ou) {
		if ($distinguishedName -match $rxOU) {$matches['OUName']}
	}
	else {
		if ($distinguishedName -match $rxPath) {
			$c,$p = $matches['CN','Path']
			$n = if ($distinguishedName -match $rxOU) {$matches['OUName']} #else {}
			$c,$n,$p
		}
	}
} # END Split-DistinguishedName

# Classic edition v2
function Split-DistinguishedName {
	param (
		[alias('dn')][string]$distinguishedName,
		[alias('leaf')][switch]$cn,
		[alias('parent')][switch]$ou,
		[switch]$path
	)
	if (-not $distinguishedName) {return}
	$parts = $distinguishedName -split '(CN=)|(OU=)|(DC=)'
	$dnparts = for ($i=2; $i -lt $parts.count; $i+=2) {
		'{0}{1}' -f $parts[$i-1], $parts[$i].TrimEnd(',')
	}
	if ($cn) {
		if ($dnparts[0] -match '^CN') {$dnparts[0] -replace 'CN='}
	} elseif ($path) {
		if ($dnparts[1]) {$dnparts[1..($dnparts.count-1)] -join ','}
	} elseif ($ou) {
		if ($dnparts[1] -match '^(CN|OU)=') {$dnparts[1] -replace 'CN=|OU='}
	} else {$dnparts}
} # END Split-DistinguishedName

split-distinguishedName 'CN=Berge, Karen,OU=fkr,CN=admin,DC=corp,DC=Fabrikam,DC=COM'
Berge, Karen

split-distinguishedName 'CN=Berge, Karen,OU=fkr,CN=admin,DC=corp,DC=Fabrikam,DC=COM' -path
OU=fkr,CN=admin,DC=corp,DC=Fabrikam,DC=COM

split-distinguishedName 'CN=Berge, Karen,CN=admin,DC=corp,DC=Fabrikam,DC=COM' -ou
admin