Trim string in Powershell using String.Replace

Question

I am trying to strip Active Directory's "DistinguishedName" attribute down to just the most specific OU title. For example, I am given:

CN=Smith\, Tom,OU=Developers,OU=Users,DC=myOrganization,DC=com

And I want this reduced to:

Developers

I have tried doing this without success (assume the variable is storing the DistinguisedName as above):

$disName = $disName.Replace("CN(*)OU=", "")
$disName = $disName.Replace(",OU(*)=com", "")

These statements are making no change to the string.

I am new to using regex in Powershell so I assume I'm just making a syntax mistake but the concept is correct.

Ansgar Wiechers · Accepted Answer · 2015-06-29 18:41:28Z

2

It's simpler to use a regular expression for this kind of data extraction, as others have already suggested, because String.Replace doesn't support things like non-greedy matches. I would recommend using a slightly more elaborate regular expression, though:

^.*?,\s*ou=(.*?),\s*(?:ou|dc).*$

because the suggestions you got so far will produce undesired results when the OU name contains characters like spaces or commas.

Demonstration:

PS C:\> $dn = 'CN=Smith\, Tom,OU=Developers\, Foo,OU=Users,DC=example,DC=com'
PS C:\> $dn -replace '^.*?,\s*ou=(.*?),\s*(?:ou|dc).*$', '$1'
Developers\, Foo
PS C:\> $dn -replace '^CN.*?OU=|,.*$'
Developers\
PS C:\> [regex]::Match($dn, 'OU=(\w+),').Groups[1].Value
Users

answered Jun 29, 2015 at 18:41

Ansgar Wiechers

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Martin Brandl · Accepted Answer · 2015-06-29 18:17:15Z

0

You could use a regex:

$attribute = "CN=Smith\, Tom,OU=Developers,OU=Users,DC=myOrganization,DC=com"    
[regex]::Match($attribute, 'OU=(\w+),').Groups[1].Value

Output:

Developers

answered Jun 29, 2015 at 18:17

Martin Brandl

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3 Comments

Bobazonski Over a year ago

Thanks! Can you explain what (\w+) and Groups[1] are doing?

Martin Brandl Over a year ago

Explaination copied from regex101.com: /OU=(\w+),/ OU= matches the characters OU= literally (case sensitive) 1st Capturing group (\w+) \w+ match any word character [a-zA-Z0-9_] Quantifier: + Between one and unlimited times, as many times as possible, giving back as needed [greedy] , matches the character , literally

Martin Brandl Over a year ago

Groups[1] selects the second group (containing the capturing group) from [regex]::Match()

vks · Accepted Answer · 2015-06-29 18:19:06Z

0

^CN.*?OU=|,.*$

You can use this and replace by empty string.See demo.

https://regex101.com/r/rX1tE6/6

answered Jun 29, 2015 at 18:19

vks

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