How to run a task once, only on installing, on android

~ $ ls /usr/share/java/ant-1.8.2/lib/ant-commons-net.jar
ls: /usr/share/java/ant-1.8.2/lib/ant-commons-net.jar: No such file or directory

~ $ ls tools/apache-ant-1.8.2/lib/ant-commons-net.jar 
tools/apache-ant-1.8.2/lib/ant-commons-net.jar

~ $ jar -tf tools/apache-ant-1.8.2/lib/ant-commons-net.jar | grep FTPTask.class
org/apache/tools/ant/taskdefs/optional/net/FTPTask.class

this.spawnCommand(installer, args, cb)
  .on('error', cb)
  .on('exit', this.emit.bind(this, installer + 'Install:end', paths))
  .on('exit', function (err) {
    if (err === 127) {
      this.log.error('Could not find ' + installer + '. Please install with ' +
                          '`npm install -g ' + installer + '`.');
    }
    cb(err);
  }.bind(this));

var spawn = require('child_process').spawn;
var win32 = process.platform === 'win32';

/**
 * Normalize a command across OS and spawn it.
 *
 * @param {String} command
 * @param {Array} args
 */

module.exports = function spawnCommand(command, args) {
  var winCommand = win32 ? 'cmd' : command;
  var winArgs = win32 ? ['/c'].concat(command, args) : args;

  return spawn(winCommand, winArgs, { stdio: 'inherit' });
};

this.on('end', function () {
  this.installDependencies({
    skipInstall: this.options['skip-install'],
    callback: function () {
      this.spawnCommand('grunt', ['build']);
    }.bind(this) // bind the callback to the parent scope
  });
});

<publications>
 <artifact name="find" type="jar" conf="core" />
 <artifact name="Documentation" type="res" ext="docx" conf="core" />
 <artifact name="Dep_report" type="res" ext="xml" conf="core" />
</publications>

<ivy:install organisation="${ivy.organisation}" module="${ivy.module}" 
    revision="${ivy.revision}" from="shared" to="released" overwrite="true" conf="core" />