proc1 = ['/bin/bash', '-c', "/usr/bin/git ls-remote -h ssh://user@server.com/path/to/repo.git"].execute()
proc2 = ['/bin/bash', '-c', "awk '{print $2}'"].execute()
proc3 = ['/bin/bash', '-c', "sed s%^refs/heads%origin%"].execute()

all = proc1 | proc2 | proc3
String result = all.text

String filename = "/tmp/branches.txt"
boolean success = new File(filename).write(result)

def multiline = "cat /tmp/branches.txt".execute().text
def list = multiline.readLines()

git ls-remote git@github.com:my/repo.git |grep refs/heads/* >tmp.txt
sed -e 's/.*refs/heads///' tmp.txt > tmp2.txt
tr 'n' ',' < tmp2.txt > tmp3.txt
sed '1ibranches=' tmp3.txt > tmp4.txt
tr -d 'n'  < tmp4.txt > branches.txt

<?php
chdir('/path/to/repo');
exec('git branch -r', $output);
print('branches='.str_replace('  origin/','',implode(',', $output)));
?>

<?php
exec('git ls-remote -h http://user:pass@repo.git', $output);
print('branches='.preg_replace('/[a-z0-9]*trefs/heads//','',implode(',', $output)));
?>

#!/usr/bin/groovy

def gitURL = "git repo url"
def command = "git ls-remote --heads --tags ${gitURL}"

def proc = command.execute()
proc.waitFor()

if ( proc.exitValue() != 0 ) {
   println "Error, ${proc.err.text}"
   System.exit(-1)
}

def text = proc.in.text
# put your version string match
def match = /<REGEX>/
def tags = []

text.eachMatch(match) { tags.push(it[1]) }
tags.unique()
tags.sort( { a, b ->
         def a1 = a.tokenize('._-')
         def b1 = b.tokenize('._-')
         try {
            for (i in 1..<[a1.size(), b1.size()].min()) {
                 if (a1[i].toInteger() != b1[i].toInteger()) return a1[i].toInteger() <=> b1[i].toInteger()
            }
            return 1
         } catch (e) {
            return -1;
         }
} )
tags.reverse()

import jenkins.model.Jenkins

def envVars = Jenkins.instance.getNodeProperties()[0].getEnvVars()
def GIT_PROJECT_PATH = envVars.get('GIT_PROJECT_PATH')
def gettags = "git ls-remote -t --heads origin".execute(null, new File(GIT_PROJECT_PATH))

return gettags.text.readLines()
         .collect { it.split()[1].replaceAll('\^\{\}', '').replaceAll('refs/\w+/', '')  }
         .unique()

proc1 = ['/bin/bash', '-c',
  "/usr/bin/git ls-remote --heads ssh://repo_url.git"].execute()
proc2 = ['/bin/bash', '-c',
  "/usr/bin/awk ' { gsub(/refs\/heads\//, ""); print $2 }' "].execute()
all = proc1 | proc2

choices = all.text
return choices.split().toList();