💡 Today I Learned

Regex with powershell - only a few things you need to know to get you started

Use operators such as -replace, -match and -split.

"fred" -replace "ed`$", "ida"

here is -split:

"a sentence? a sentence! a sentence." -split "[!?.]"

returns:

a sentence
 a sentence
 a sentence

There's -match and -notmatch and case sensitive variants: -cmatch and -cnotmatch

After -match is used, the variable $matches will hold the matches, e.g.

"fred" -match "^fr(.*)";$matches

returns:

True

Name                           Value
----                           -----
1                              ed
0                              fred

Regex Options With Powershell

Include 1 option...

$options = [Text.RegularExpressions.RegexOptions]::Singleline
$match = [regex]::Match($input, $regex, $options)

Include multiple options by using a "bitwise or" (-bor):

$options = [Text.RegularExpressions.RegexOptions]::IgnoreCase -bor [Text.RegularExpressions.RegexOptions]::CultureInvariant
$match = [regex]::Match($input, $regex, $options)

That's a lot of typing... instead, "let casting do the magic" like so:

$options = [Text.RegularExpressions.RegexOptions]'IgnoreCase, CultureInvariant'
$match = [regex]::Match($input, $regex, $options)

Regex Replace with a Lambda or ScriptBlock in Powershell

$callback = {
  param($match)
  'This is the image: ' + (Get-Base64 $match.Groups[1].Value)
}

$re = [regex]'-(\d*)-'
$result = $re.Replace("the image is -12345-", $callback)

Source