Make docker command detection consistently across OSes

build.gradle

@@ -120,7 +120,7 @@ jacocoTestReport {
     }
 }
 
-String version = '5.2.0'
+String version = '5.3.0'
 
 task updateVersion {
     doLast {

tests/jenkins/jobs/RunGradleCheck_Jenkinsfile.txt

@@ -37,11 +37,11 @@
                 ./gradlew --stop
                 rm -rf ~/.gradle
 
-                if ! (uname -s | grep -i NT); then
+                if command -v docker > /dev/null; then
                     echo "Check existing dockercontainer"
                     docker ps -a
                     docker stop `docker ps -qa` > /dev/null 2>&1 || echo
-                    docker rm `docker ps -qa` > /dev/null 2>&1 || echo
+                    docker rm --force `docker ps -qa` > /dev/null 2>&1 || echo
                     echo "Stop existing dockercontainer"
                     docker ps -a
 

vars/runGradleCheck.groovy

@@ -51,11 +51,11 @@ void call(Map args = [:]) {
                 ./gradlew --stop
                 rm -rf ~/.gradle
 
-                if ! (uname -s | grep -i NT); then
+                if command -v docker > /dev/null; then
                     echo "Check existing dockercontainer"
                     docker ps -a
                     docker stop `docker ps -qa` > /dev/null 2>&1 || echo
-                    docker rm `docker ps -qa` > /dev/null 2>&1 || echo
+                    docker rm --force `docker ps -qa` > /dev/null 2>&1 || echo
                     echo "Stop existing dockercontainer"
                     docker ps -a