Perl file ("changePomVersion.pl") to change version of an artifact in a pom.xml.

changePomVersion.pl

#!/usr/bin/perl

# This file takes 2 arguments when run: 
# -p <POMFILE>
# -v <VERSION>
#
# The <POMFILE> argument is the path to a pom.xml file whose version should be changed
# The <VERSION> argument is the new version that should replaced the existing version
#

use File::Copy;

# - Retrieve options
use Getopt::Std;

getopts('p:v:');

my $pomFile, $newVer;

if( $opt_v ) { 
  $newVer = $opt_v;
} else { 
  die "New version required.\n";
}

if( $opt_p ) { 
  $pomFile = $opt_p;
} else { 
  die "Pom file required.\n";
}

my $versionLineMax = 100;

# - Print options/info
print "Changing $pomFile ($newVer)\n";

# Open original file
open( POM, "<$pomFile" ) 
  || die "Unable to open $pomFile for reading: $!\n";

# Open new file that will replace original
open( NEWPOM, ">$pomFile.new" ) 
  || die "Unable to open $pomFile.new for writing: $!\n";

# Flag to indicate that it's the first <version> element after the </parent> element
$afterParent = 0;
$lineCount = 0;

# Read through POM data (each line is put in the $_ variable
while(<POM>) { 

  ++$lineCount;
  # Flag to indicate that the line has been modified and already printed to NEWPOM
  $replaced = 0;

  # Does the line contain </parent>? 
  if( m#^\s*</parent># ) { 
    ++$afterParent;
  } elsif( m#^\s*<version># ) { 
    # If </parent> occurs multiple times, just replace <version> element 
    # after the *first* <parent>
    if( $afterParent == 1 ) { 
      # double check line number
      if( $lineCount > $versionLineMax ) { 
        die "Failling because first <version> element was found after line $versionLineMax!\n";
      }

      # replace original version with $newVer value
      $newline = $_;
      $newline =~ s#<version>([^<]+)</version>#<version>$newVer</version>#;
      print NEWPOM $newline;
      $replaced = 1;
    }
  }
 
  if( ! $replaced ) { 
    # print unmodified lines to new pom file
    print NEWPOM $_;
  }
}

close( POM );
close( NEWPOM );

# replace original pomFile with modified copy
move("$pomFile.new", $pomFile) 
  || die "Unable to replace $pomFile with ${pomFile}.new: $!\n";