[bash] How to get Maven project version to the bash command line

Previous I issued a question on how to change Maven project vesion from command line which lead me to a new issue.

Previously I was able to get the version number since the version was stored as a property that was easy to grep and parse from the command line (bash). Now that the pom.xml <version> element is used for this, it no longer is unique since all the dependencies and maybe some others too use this. I think there is no way to get the current version number with a bash script without external tools for parsing XML or some very context-aware sed command.

The most clean solution in my opinion would be for Maven to hand out this version information. I was thinking of writing a custom maven plugin for retrieving different properties but I thought I'd ask here first.

So, is there any easy way to get the value of ${project.version} to the command line?

Solution

I had to cd to the directory manually but that can be done easily. In my bash script I have:

version=`cd $project_loc && mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | sed -n -e '/^\[.*\]/ !{ /^[0-9]/ { p; q } }'`

Which gives me the current version that I can then advance. Grepping might be simpler but I thought I'd like as robust as possible, so I'm satisfied with the first line that starts with a number and try to handle this as a version number.

# Advances the last number of the given version string by one.
function advance_version () {
    local v=$1
    # Get the last number. First remove any suffixes (such as '-SNAPSHOT').
    local cleaned=`echo $v | sed -e 's/[^0-9][^0-9]*$//'`
    local last_num=`echo $cleaned | sed -e 's/[0-9]*\.//g'`
    local next_num=$(($last_num+1))
    # Finally replace the last number in version string with the new one.
    echo $v | sed -e "s/[0-9][0-9]*\([^0-9]*\)$/$next_num/"
}

And I use this by simply calling:

new_version=$(advance_version $version)

I kept running into side cases when using some of the other answers here, so here's yet another alternative.

version=$(printf 'VER\t${project.version}' | mvn help:evaluate | grep '^VER' | cut -f2)

The top answer is pretty garbage in my opinion, you have to use a bunch of grep to hack out the maven console output. Why not use the right tool for the job? Using xpath syntax is the best approach to retrieving the version number, since it is the intended method of accessing a XML data structure. The expression below is traversing the pom using the "local name" of the elements, in other words ignoring namespace declarations which may or may not be present in the xml.

xmllint --xpath "//*[local-name()='project']/*[local-name()='version']/text()" pom.xml

Base on the question, I use this script below to automatic increase my version number in all maven parent/submodules:

#!/usr/bin/env bash  

# Advances the last number of the given version string by one.  
function advance\_version () {  
    local v=$1  
    \# Get the last number. First remove any suffixes (such as '-SNAPSHOT').  
  local cleaned=\`echo $v | sed \-e 's/\[^0-9\]\[^0-9\]\*$//'\`  
 local last\_num=\`echo $cleaned | sed \-e 's/\[0-9\]\*\\.//g'\`  
 local next\_num=$(($last\_num+1))  
  \# Finally replace the last number in version string with the new one.  
  echo $v | sed \-e "s/\[0-9\]\[0-9\]\*\\(\[^0-9\]\*\\)$/$next\_num/"  
}  

version=$(mvn org.apache.maven.plugins:maven-help-plugin:3.2.0:evaluate -Dexpression=project.version -q -DforceStdout)  

new\_version=$(advance\_version $version)  

mvn versions:set -DnewVersion=${new\_version} -DprocessAllModules -DgenerateBackupPoms=false

Either you have mvn give you the answer (as most answers suggest), or you extract the answer from the pom.xml. The only drawback of the second approach is that you can very easily extract the value of the <version/> tag, but it will be meaningful only if it's literal, that is, not a Maven property. I chose this approach anyway because:

• mvn is way to verbose and I simply don't like filtering its output.
• Starting mvn is very slow compared to reading the pom.xml.
• I always use literal values in <version/>.

mvn-version is a zsh shell script that uses xmlstarlet to read the pom.xml and print the version of the project (if it exists) or the version of the parent project (if it exists):

$ mvn-version .
1.0.0-SNAPSHOT

The advantage is that it's way quicker than running mvn:

$ time mvn-version .
1.1.0-SNAPSHOT
mvn-version .  0.01s user 0.01s system 75% cpu 0.019 total

$ time mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate \
> -Dexpression=project.version
mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate   4.17s user 0.21s system 240% cpu 1.823 total

The difference on my machine is greater than two orders of magnitude.

Exec plugin works without any output parsing because output can be redirected into file and injected back into the job environment via EnvInject plugin:

I am using a one-liner in my unix shell ...

cat pom.xml | grep "" | head -n 1 | sed -e "s/version//g" | sed -e "s/\s*[<>/]*//g"

You can hide this line in a shell script or as an alias.

Should be easier since this bug is fixed in maven-help-plugin 3.0.0: MPH-99 Evaluate has no output in quiet mode.

python -c "import xml.etree.ElementTree as ET; \
  print(ET.parse(open('pom.xml')).getroot().find( \
  '{http://maven.apache.org/POM/4.0.0}version').text)"

As long as you have python 2.5 or greater, this should work. If you have a lower version than that, install python-lxml and change the import to lxml.etree. This method is quick and doesn't require downloading any extra plugins. It also works on malformed pom.xml files that don't validate with xmllint, like the ones I need to parse. Tested on Mac and Linux.

This is the cleanest solution there is:

mvn org.apache.maven.plugins:maven-help-plugin:3.2.0:evaluate \
-Dexpression=project.version -q -DforceStdout

Advantages:

• This works fine on all operating systems and all shells.
• No need for any external tools!
• [important] This works even if project version is inherited from parent pom.xml

Note:

• maven-help-plugin version 3.2.0 (and above) has forceStdout option. You may replace 3.2.0 in above command with a newer version from the list of available versions of mvn-help-plugin from artifactory, if available.
• Option -q suppresses verbose messages ([INFO], [WARN] etc.)

Alternatively, you can add this entry in your pom.xml, under plugins section:

<plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-help-plugin</artifactId>
    <version>3.2.0</version>
</plugin>

and then run above command compactly as follows:

mvn help:evaluate -Dexpression=project.groupId -q -DforceStdout

If you want to fetch groupId and artifactId as well, check this answer.

I found right balance for me. After mvn package maven-archiver plugin creates target/maven-archiver/pom.properties with contents like this

version=0.0.1-SNAPSHOT
groupId=somegroup
artifactId=someArtifact

and I am using bash just to execute it

. ./target/maven-archiver/pom.properties

then

echo $version
0.0.1-SNAPSHOT

Of course this is not safe at all to execute this file, but execution can easily be converted into perl or bash script to read and set environment variable from that file.

mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | grep -v '\['

I need exactly this requirement during my Travis job but with multiple values. I start with this solution but when calling multiple time this is very slow (I need 5 expresions).

I wrote a simple maven plugin to extract pom.xml's values into .sh file.

https://github.com/famaridon/ci-tools-maven-plugin

mvn com.famaridon:ci-tools-maven-plugin:0.0.1-SNAPSHOT:environment -Dexpressions=project.artifactId,project.version,project.groupId,project.build.sourceEncoding

Will produce that:

#!/usr/bin/env bash
CI_TOOLS_PROJECT_ARTIFACTID='ci-tools-maven-plugin';
CI_TOOLS_PROJECT_VERSION='0.0.1-SNAPSHOT';
CI_TOOLS_PROJECT_GROUPID='com.famaridon';
CI_TOOLS_PROJECT_BUILD_SOURCEENCODING='UTF-8';

now you can simply source the file

source .target/ci-tools-env.sh

Have fun.

This will avoid the need for grepping off log entries from the output:

mvn -Dexec.executable='echo' -Dexec.args='${project.version}' --non-recursive exec:exec -q

The easy to understand all-in-one solution that outputs the maven project version, and suppresses extraneous output from [INFO] and Download messages:

mvn -o org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | grep -v '\['

Same thing, but split onto two lines:

mvn -o org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate \
      -Dexpression=project.version | grep -v '\['

Outputs: 4.3-SNAPSHOT

So, using your project.version in a simple bash script:

projectVersion=`mvn -o org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | grep -v '\['`
cd "target/"$projectVersion"-build"

Other solutions on this page didn't seem to combine all the tricks into one.

A simple maven only solution

mvn -q -N org.codehaus.mojo:exec-maven-plugin:1.3.1:exec \
    -Dexec.executable='echo' \
    -Dexec.args='${project.version}'

And for bonus points parsed part of a version

mvn -q -N org.codehaus.mojo:build-helper-maven-plugin:3.0.0:parse-version \
    org.codehaus.mojo:exec-maven-plugin:1.3.1:exec \
    -Dexec.executable='echo' \
    -Dexec.args='${parsedVersion.majorVersion}.${parsedVersion.minorVersion}.${parsedVersion.incrementalVersion}'

There is also one option without need Maven:

grep -oPm1 "(?<=<version>)[^<]+" "pom.xml"

I noticed some spurious Downloaded: lines coming in the output that were breaking my original assignment. Here's the filter I've settled on; hope it helps!

version=$(mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | egrep -v '^\[|Downloading:' | tr -d ' \n')

EDIT

Not 100% sure why, but when running this through a post-build script in Jenkins, the output was coming out as [INFO]version, e.g. [INFO]0.3.2.

I dumped the output to a file and ran it through my first filter directly from BASH, it works fine.., so again, unsure what's going on in Jenkins land.

To get it 100% in Jenkins, I've added a follow-up sed filter; here's my latest

version=$(mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version | egrep -v '^\[|Downloading:' | tr -d ' \n' | sed -E 's/\[.*\]//g')

EDIT

One last note here.. I found out tr was still resulting in things like /r/n0.3.2 (again only when running via Jenkins). Switched to awk and the problem has gone away! My final working result

mvn org.apache.maven.plugins:maven-help-plugin:2.1.1:evaluate -Dexpression=project.version \
| egrep -v '^\[|Downloading:' | sed 's/[^0-9\.]//g' | awk 1 ORS=''

I've recently developed the Release Candidate Maven plugin that solves this exact problem so that you don't have to resort to any hacky shell scripts and parsing the output of the maven-help-plugin.

For example, to print the version of your Maven project to a terminal, run:

mvn com.smartcodeltd:release-candidate-maven-plugin:LATEST:version

which gives output similar to maven-help-plugin:

[INFO] Detected version: '1.0.0-SNAPSHOT'
1.0.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

However, you can also specify an arbitrary output format (so that the version could be picked up from the log by a CI server such as TeamCity):

mvn com.smartcodeltd:release-candidate-maven-plugin:LATEST:version \
   -DoutputTemplate="##teamcity[setParameter name='env.PROJECT_VERSION' value='{{ version }}']"

Which results in:

[INFO] Detected version: '1.0.0-SNAPSHOT'
##teamcity[setParameter name='env.PROJECT_VERSION' value='1.0.0-SNAPSHOT']
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------

To save the output to a file (so that a CI server such as Jenkins could use it):

mvn com.smartcodeltd:release-candidate-maven-plugin:LATEST:version \
   -DoutputTemplate="PROJECT_VERSION={{ version }}" \
   -DoutputUri="file://\${project.basedir}/version.properties"

The resulting version.properties file will look as follows:

PROJECT_VERSION=1.0.0-SNAPSHOT

On top of all the above, Release Candidate also allows you to set the version of your project (which is something you'd probably do on your CI server) based on the API version you've defined in your POM.

If you'd like to see an example of Release Candidate being used as part of the Maven lifecycle, have a look at the pom.xml of my other open-source project - Build Monitor for Jenkins.

One alternative would be to parse with yq (https://github.com/kislyuk/yq) like so:

cat pom.xml | xq -r '.project.version'

Notice the executable is xq not yq

To get xq, install yq like so pip install yq

This worked for me, offline and without depending on mvn:

VERSION=$(grep --max-count=1 '<version>' <your_path>/pom.xml | awk -F '>' '{ print $2 }' | awk -F '<' '{ print $1 }')
echo $VERSION

VERSION=$(head -50 pom.xml | awk -F'>' '/SNAPSHOT/ {print $2}' | awk -F'<' '{print $1}')

This is what I used to get the version number, thought there would have been a better maven way to do so

I have been doing some research and found the following:

1. Maven has been blamed because integration with DevOps tools is not easy due to the fact that it does not follow some good practices regarding CLI tools. (ref: https://youtu.be/1ILEw6Qca3U?t=372)

2. Inspired on the previous assertion, I decided to give a look on maven's source code as well as on maven-help-plugin. It seems that they have fixed a little bit the maven's -q switch (I am using version 3.5.3), so now if you pass it, you won't get all the annoying non-sense logging stuff that prevents maven from being used within automated scripts. So you should be able to use something like this:

   mvn help:evaluate -Dexpression=project.version -q
   

   The problem is that this command prints nothing because by default the help plugin outputs through the logger which has been silenced by the -q switch. (latest available version of the plugin is 3.1.0 released on June, 3rd 2018)

3. Karl Heinz Marbaise (https://github.com/khmarbaise) fixed it by adding an optional parameter that allows you to call it in the following way:

   mvn help:evaluate -Dexpression=project.version -q -DforceStdout
   

   The commit description is available at: (https://github.com/apache/maven-help-plugin/commit/316656983d780c04031bbadd97d4ab245c84d014)

If you don't mind to write the version into a temporary file, there is another solution (without grep/sed) that works well for me. (EDIT: see rjrjr's answer for a much simpler solution without any temporary file hassle)

I use the Exec Maven Plugin along with the echo binary. In contrast to the Maven Help Plugin, the Exec Plugin allows output redirection into a file, which can be used to bypass grep/sed, and makes it even possible to parse strange things like multiline version strings (with CDATA block in version tag), at least to a certain extent.

#!/usr/bin/env sh

MVN_VERSION=""
VERSION_FILE=$( mktemp mvn_project_version_XXXXX )
trap "rm -f -- \"$VERSION_FILE\"" INT EXIT

mvn -Dexec.executable="echo" \
    -Dexec.args='${project.version}' \
    -Dexec.outputFile="$VERSION_FILE" \
    --non-recursive \
    --batch-mode \
    org.codehaus.mojo:exec-maven-plugin:1.3.1:exec > /dev/null 2>&1 ||
    { echo "Maven invocation failed!" 1>&2; exit 1; }

# if you just care about the first line of the version, which will be
# sufficent for pretty much every use case I can imagine, you can use
# the read builtin
[ -s "$VERSION_FILE" ] && read -r MVN_VERSION < "$VERSION_FILE"

# Otherwise, you could use cat.
# Note that this still has issues when there are leading whitespaces
# in the multiline version string
#MVN_VERSION=$( cat "$VERSION_FILE" )

printf "Maven project version: %s\n" "$MVN_VERSION"

In docker containers with only busybox available I use awk.

version=$(
 awk '
  /<dependenc/{exit}
  /<parent>/{parent++};
  /<version>/{
    if (parent == 1) {
      sub(/.*<version>/, "");
      sub(/<.*/, "");
      parent_version = $0;
    } else {
      sub(/.*<version>/, "");
      sub(/<.*/, "");
      version = $0;
      exit
    }
  }
  /<\/parent>/{parent--};
  END {
    print (version == "") ? parent_version : version
  }' pom.xml
)

Notes:

• If no artifact version is given parent version is printed instead.
• Dependencies are required to come after artifact and parent version. (This could be overcome quite easily but I don't need it.)

Just for the record, it's possible to configure Maven's Simple SLF4J logging directly in the command line to output only what we need by configuring:

• org.slf4j.simpleLogger.defaultLogLevel=WARN and
• org.slf4j.simpleLogger.log.org.apache.maven.plugins.help=INFO

as documented at http://www.slf4j.org/api/org/slf4j/impl/SimpleLogger.html

MAVEN_OPTS="\
-Dorg.slf4j.simpleLogger.defaultLogLevel=WARN \
-Dorg.slf4j.simpleLogger.log.org.apache.maven.plugins.help=INFO" \
mvn help:evaluate -o -Dexpression=project.version

As a result, one can run simply tail -1 and get:

$ MAVEN_OPTS="\
-Dorg.slf4j.simpleLogger.defaultLogLevel=WARN \
-Dorg.slf4j.simpleLogger.log.org.apache.maven.plugins.help=INFO" \
mvn help:evaluate -o -Dexpression=project.version | tail -1

1.0.0-SNAPSHOT

Note that this is a one-liner. MAVEN_OPTS are being rewritten only for this particular mvn execution.

this is an edit from above

cat pom.xml | grep "" | head -n 1 | sed -e "s/version//g" | sed -e "s/\s*[<>/]*//g"

I tested it out on on the cmdline works well

grep "" pom.xml | head -n 1 | sed -e "s/version//g" | sed -e "s/\s*[<>/]*//g"

is another version of the same. I have a need to get the version number in Jenkins CI in k8s without mvn installed so this is most helpful

thanks all.

This is by far the easiest bash cut and paste solution:

VERSION=$(mvn -Dexec.executable='echo' -Dexec.args='${project.version}' --non-recursive exec:exec -q)
echo $VERSION

it echoes

1.4

Tom's solution with the Exec Maven Plugin is much better, but still more complicated than it needs to be. For me it's as simple as:

MVN_VERSION=$(mvn -q \
    -Dexec.executable=echo \
    -Dexec.args='${project.version}' \
    --non-recursive \
    exec:exec)

mvn help:evaluate -Dexpression=project.version | sed -e 1h -e '2,3{H;g}' -e '/\[INFO\] BUILD SUCCESS/ q' -e '1,2d' -e '{N;D}' | sed -e '1q'

I'm just adding small sed filter improvement I have recently implemented to extract project.version from maven output.