14

I want to read a pom.xml ('Project Object Model' of Maven) and extract the version information. Here is an example:

<?xml version="1.0" encoding="UTF-8"?><project 
xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <groupId>com.mycompany</groupId>
    <artifactId>project-parent</artifactId>
    <name>project-parent</name>
    <version>1.0.74-SNAPSHOT</version>
    <dependencies>
        <dependency>
        <groupId>com.sybase.jconnect</groupId>
        <artifactId>jconnect</artifactId>
        <version>6.05-26023</version>
    </dependency>
    <dependency>
        <groupId>joda-time</groupId>
        <artifactId>joda-time</artifactId>
        <version>1.5.2</version>
    </dependency>
    <dependency>
        <groupId>com.sun.jdmk</groupId>
        <artifactId>jmxtools</artifactId>
        <version>1.2.1</version>
    </dependency>
    <dependency>
        <groupId>org.easymock</groupId>
        <artifactId>easymock</artifactId>
        <version>2.4</version>
    </dependency>       
</dependencies>
</project>

How can I extract the version '1.0.74-SNAPSHOT' from above?

Would love to be able to do so using simple bash scripting sed or awk. Otherwise a simple python is preferred.

EDIT

  1. Constraint

    The linux box is in a corporate environment so I can only use tools that are already installed (not that I cannot request utility such as xml2, but I have to go through a lot of red-tape). Some of the solutions are very good (learn a few new tricks already), but they may not be applicable due to the restricted environment

  2. updated xml listing

    I added the dependencies tag to the original listing. This will show some hacky solution may not work in this case

  3. Distro

    The distro I am using is RHEL4

6
  • Is this stackoverflow.com/questions/29004/… sufficient?
    – bbaja42
    Dec 20, 2011 at 22:08
  • Not really. There are a lot of version tag in the xml (e.g. under dependencies tag). I only want '/project/version' Dec 20, 2011 at 22:20
  • Which xml-related tools and libraries are available? Are jvm-based soltuions OK?
    – Vi.
    Dec 20, 2011 at 23:22
  • So far I can tell xml2, xmlgrep and perl XML module are not present. Most unix command-line utilities are present. The distro is Redhat EL 4. Dec 20, 2011 at 23:38
  • (I couldn't add a comment so I have to reply as an answer, overkill somewhat) Some great answers can be found here..... stackoverflow.com/questions/2735548/…
    – JStrahl
    Jan 18, 2013 at 10:12

14 Answers 14

18

xml2 can convert xml to/from line-oriented format:

xml2 < pom.xml  | grep /project/version= | sed 's/.*=//'
1
7

Other way: xmlgrep and XPath:

xmlgrep --text_only '/project/version' pom.xml

Disadvantage: slow

1
  • 1
    command updated to xml_grep
    – GAD3R
    May 1, 2019 at 11:05
6

Using python

$ python -c 'from xml.etree.ElementTree import ElementTree; print ElementTree(file="pom.xml").findtext("{http://maven.apache.org/POM/4.0.0}version")'
1.0.74-SNAPSHOT

Using xmlstarlet

$ xml sel -N x="http://maven.apache.org/POM/4.0.0" -t -m 'x:project/x:version' -v . pom.xml
1.0.74-SNAPSHOT

Using xmllint

$ echo -e 'setns x=http://maven.apache.org/POM/4.0.0\ncat /x:project/x:version/text()' | xmllint --shell pom.xml | grep -v /
1.0.74-SNAPSHOT
1
  • cat (//x:version)[1]/text() when using xmllint also works!
    – kev
    Dec 21, 2011 at 5:50
5

Clojure way. Requires only jvm with special jar file:

java -cp clojure.jar clojure.main -e "(use 'clojure.xml) (->> (java.io.File. \"pom.xml\") (clojure.xml/parse) (:content) (filter #(= (:tag %) :version)) (first) (:content) (first) (println))"

Scala way:

java -Xbootclasspath/a:scala-library.jar -cp scala-compiler.jar scala.tools.nsc.MainGenericRunner -e 'import scala.xml._; println((XML.load(new java.io.FileInputStream("pom.xml")) match { case <project>{children @ _*}</project> => for (i <- children if (i  match { case <version>{children @ _*}</version> => true; case _ => false;  }))  yield i })(0) match { case <version>{Text(x)}</version> => x })'

Groovy way:

java -classpath groovy-all.jar groovy.ui.GroovyMain -e 'println (new XmlParser().parse(new File("pom.xml")).value().findAll({ it.name().getLocalPart()=="version" }).first().value().first())'
1
  • This is awesome! Great idea! Dec 21, 2011 at 0:06
4

Here's an alternative in Perl

$ perl -MXML::Simple -e'print XMLin("pom.xml")->{version}."\n"'
1.0.74-SNAPSHOT

It works with the revised/extended example in the questions which has multiple "version" elements at different depths.

1
  • Slow, (although faster than xmlgrep)
    – Vi.
    Dec 20, 2011 at 22:58
3

Hacky way:

perl -e '$_ = join "", <>; m!<project[^>]*>.*\n(?:    |\t)<version[^>]*>\s*([^<]+?)\s*</version>.*</project>!s and print "$1\n"' pom.xml

Relies on correct indentation of the required <version>

7
  • Thanks for the suggestion, but unfortunately it will not return what I want. Please see the updated pom model. Dec 20, 2011 at 23:14
  • Returns "1.0.74-SNAPSHOT". Note that I changed the script after reading about multiple <version> things.
    – Vi.
    Dec 20, 2011 at 23:17
  • Note: this solution is provided "just for fun" and is not intended to be used in actual product. Better use xml2/xmlgrep/XML::Simple solution.
    – Vi.
    Dec 20, 2011 at 23:18
  • Thanks! even though it is 'just for fun' but it is probably the 'most suitable' solution by far because it has minimum number of dependencies: It only requires perl ;-) Dec 20, 2011 at 23:22
  • What about doing it from Java? Using pom files implies having JVM installed.
    – Vi.
    Dec 20, 2011 at 23:25
3

Work out a very clumsy, one-liner solution

python -c "from xml.dom.minidom import parse;dom = parse('pom.xml');print [n for n in dom.getElementsByTagName('version') if n.parentNode == dom.childNodes[0]][0].toxml()" | sed -e "s/.*>\(.*\)<.*/\1/g"

The sed at the end is very ugly but i was not able to print out the text of the node with mindom alone.

Update from _Vi:

Less hacky Python version:

python -c "from xml.dom.minidom import parse;dom = parse('pom.xml');print [i.childNodes.item(0).nodeValue for i in dom.firstChild.childNodes if i.nodeName == 'version'].pop()"

Update from me

Another version:

    python -c "from  xml.dom.minidom import parse;dom = parse('pom.xml');print [n.firstChild.data for n in dom.childNodes[0].childNodes if n.firstChild and n.tagName == 'version']"
2

XSLT way:

<?xml version="1.0" encoding="ISO-8859-1"?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
        <xsl:output method="text"/>

        <xsl:template match="/">
                <xsl:for-each select="*[local-name()='project']">
                    <xsl:for-each select="*[local-name()='version']">
                        <xsl:value-of select="text()"/>
                    </xsl:for-each>
                </xsl:for-each>
        </xsl:template>
</xsl:stylesheet>
xalan -xsl x.xsl -in pom.xml
1
  • If xsltproc is on your system, and it probably is as libxslt is on RHEL4, then you can use it and the above stylesheet to output the tag, i.e. xsltproc x.xsl prom.xsl.
    – fpmurphy
    Dec 21, 2011 at 5:12
2

if "There are a lot of version tag in the xml" then you better forget about doing it with "simple tools" and regexps, that won't do.

try this python (no dependencies):

from xml.dom.minidom import parse

dom = parse('pom.xml')
project = dom.getElementsByTagName('project')[0]
for node in project.childNodes:
    if node.nodeType == node.ELEMENT_NODE and node.tagName == 'version':
        print node.firstChild.nodeValue
2
  • What exactly does this script do? Dec 22, 2011 at 1:41
  • it loads the XML as a DOM structure using Python's minidom implementation: docs.python.org/library/xml.dom.minidom.html the idea is to grab the <project> tag that is unique and then iterate over its child nodes (direct childs only) to find the tag <version> that we're looking for and not other tags with the same name in other places.
    – Samus_
    Dec 22, 2011 at 15:17
1

Here is a one-liner using sed:

sed '/<dependencies>/,/<\/dependencies>/d;/<version>/!d;s/ *<\/\?version> *//g' pom.xml
1
  • 1
    Relies on absence of parameters in elements and that extra <version>s can be only inside dependencies.
    – Vi.
    Dec 21, 2011 at 16:33
1

I know your question says Linux but if you have the need to do this on Windows without the need of any 3rd party tools such that you can put it in a batch file, Powershell can extract any node from the your pom.xml file like so:

powershell -Command "& {select-xml //pom:project/pom:properties/pom:mypluginversion -path pom.xml -Namespace  @{pom='http://maven.apache.org/POM/4.0.0'} | foreach {$_.Node.Innerxml}}" > myPluginVersion.txt
1
  • Powershell is now open source and runs on Linux and other platforms. We use it for building in preference to bash, cygwin and ming64.
    – Charlweed
    Aug 1, 2019 at 21:54
1

awk works fine without using any extra tools.
cat pod.xml

<project>
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.networks.app</groupId>
  <artifactId>operation-platform</artifactId>
  <version>1.0.0</version>
  <packaging>tar.xz</packaging>
  <description>POM was created by Sonatype Nexus</description>
</project>

simple and legible way to get the value of <packaging> tag:

cat pod.xml | awk -F'[<>]' '/packaging/{print $3}'
1
  • 1
    This does appear to work, but beware: What it does is set the field separator (FS) to the set of characters < and >; then it finds all lines with the word "packaging" in them and give you the third field.
    – SMerrill8
    Feb 11, 2020 at 23:44
0
Return_text_val=$(xmllint --xpath "//*[local-name()='$TagElmnt']" $FILE )

Here, try this:

$TagElmnt - TagName
$FILE - xml file to parse
0
0
sed -n "/<name>project-parent/{n;s/.*>\(.*\)<.*/\1/p;q}" pom.xml

The -n option avoids printing non-matching lines; first match (/.../) is on the line before the one with wanted text; the n command skips to next line, where s extracts relevant info thru a capturing group (\(...\)), and a backreference (\1). p prints out, q quits.

1
  • 2
    Can you expand your answer to explain this? Thanks.
    – fixer1234
    Oct 27, 2015 at 1:42

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