Grabbing version strings with PowerShell

The jpackage tool, which is part of OpenJDK since Java 14, can create, well, native packages. Some time ago I wrote a small piece about it, called A quick look at jpackage. In that article I showed how to grab a version string from a Java source file and pass it to jpackage which has an option called --app-version. This is how the version is defined in Java:

public class Clip4Moni {

  public static final String VERSION = "1.3.3";

  public static void main(String[] args) {

And grabbing it might look like this:

VERSION=`sed -n -e 's/.*VERSION = \"\(.*\)\".*/\1/p' < $BASEDIR/src/main/classes/com/thomaskuenneth/clip4moni/Clip4Moni.java`
$JAVA_HOME/bin/jpackage --name Clip4Moni --icon $BASEDIR/artwork/Clip4Moni.icns --app-version $VERSION --type app-image --module-path $BASEDIR/build/modules -m main/com.thomaskuenneth.clip4moni.Clip4Moni

As you can see I am using the sed commandline tool. This was designed for macOS but should run on any other Unix-like system. But what about Windows? Windows has the ancient (no offense intended) cmd.exe and the much much more modern PowerShell. PowerShell has a lot of great builtin capabilities, and handling regular expressions is among them. So it should be easy to do something similar, right? Right.

$version = "???"
$source = Get-Content -Path $base_dir\src\main\classes\com\thomaskuenneth\clip4moni\Clip4Moni.java
foreach($line in $source) {
    if ($line -match "version = `"(.+)`"") {
        $version = $matches[1]
        break
    }
}

The version string will be stored in a variable called $version. I initialize it to ???, just in case... Get-Content gets the contents of the source file. As you surely have guessed it is an array of strings. I iterate over it until my regular expression matches. (.+) is a group, which can later be accessed through $matches[1]. break exits the foreach loop.

Well, and that's all about it. Really nice, isn't it?

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Cover image Copyright (c) Thomas Künneth