Extracting a specific value from command-line output using powershell

Question

Here's the problem: I want to query subversion for the revision number of a repository, and then create a new directory with the revision number in its name (for example, "Build763").

The command "svn info" outputs a number of label\value pairs, delimited by colons. For example

Path: c#
URL: file:///%5Copdy-doo/Archive%20(H)/Development/CodeRepositories/datmedia/Development/c%23
Repository UUID: b1d03fca-1949-a747-a1a0-046c2429f46a
Revision: 58
Last Changed Rev: 58
Last Changed Date: 2011-01-12 11:36:12 +1000 (Wed, 12 Jan 2011)

Here is my current code which solves the problem. Is there a way to do this with less code? I'm thinking that with the use of piping you could do this with one or two lines. I certainly shouldn't have to use a temporary file.

$RepositoryRoot = "file:///%5Cdat-ftp/Archive%20(H)/Development/CodeRepositories/datmedia"
$BuildBase="/Development/c%23"
$RepositoryPath=$RepositoryRoot + $BuildBase

# Outputing the info into a file
svn info $RepositoryPath | Out-File -FilePath svn_info.txt

$regex = [regex] '^Revision: (\d{1,4})'

foreach($info_line in get-content "svn_info.txt")
    {
        $match = $regex.Match($info_line);
        if($match.Success)
        {
            $revisionNumber = $match.Groups[1];
            break;
        }
    }


"Revision number = " + $revisionNumber;

Answer 1

Here's one way:

    $revisionNumber = svn info $RepositoryPath |
     select-string "^revision" |
      foreach {$_.line.split(":")[1].trim()}

    if ($revisionNumber){"Revision number = " + $revisionNumber

}

Answer 2

Taking mjolinor's suggestion, I'm finally going with:

$revisionNumber = (svn info $RepositoryPath | select-string '^Revision: (\d+)$').Matches[0].Groups[1].Value

Cool! One line of code. (It took two hours to write, but hey)