diff --git a/.travis/build-deploy.sh b/.travis/build-deploy.sh
index 757a5a8c7d..424ef6a70e 100644
--- a/.travis/build-deploy.sh
+++ b/.travis/build-deploy.sh
@@ -6,12 +6,12 @@ source .travis/common-functions.sh
 VERSION=$(./mvnw -q -Dexec.executable="echo" -Dexec.args='${project.version}' --non-recursive org.codehaus.mojo:exec-maven-plugin:1.5.0:exec | tail -1)
 echo "Building PMD ${VERSION} on branch ${TRAVIS_BRANCH}"
 
-if [ travis_isPullRequest ]; then
+if travis_isPullRequest; then
 
     echo "This is a pull-request build"
     ./mvnw verify -B -V
 
-elif [ travis_isPush ]; then
+elif travis_isPush; then
 
     if [[ "$VERSION" != *-SNAPSHOT && "$TRAVIS_TAG" != "" ]]; then
         echo "This is a release build for tag $TRAVIS_TAG"
diff --git a/.travis/build-site.sh b/.travis/build-site.sh
index 15d1e5d815..07993c342d 100644
--- a/.travis/build-site.sh
+++ b/.travis/build-site.sh
@@ -6,7 +6,7 @@ source .travis/common-functions.sh
 VERSION=$(./mvnw -q -Dexec.executable="echo" -Dexec.args='${project.version}' --non-recursive org.codehaus.mojo:exec-maven-plugin:1.5.0:exec | tail -1)
 echo "Building PMD Site ${VERSION} on branch ${TRAVIS_BRANCH}"
 
-if [ ! travis_isPush ]; then
+if ! travis_isPush; then
     echo "Not building site, since this is not a push!"
     exit 0
 fi
diff --git a/.travis/build-sonar.sh b/.travis/build-sonar.sh
index 984a8532bf..19ea2009fb 100644
--- a/.travis/build-sonar.sh
+++ b/.travis/build-sonar.sh
@@ -6,7 +6,7 @@ source .travis/common-functions.sh
 VERSION=$(./mvnw -q -Dexec.executable="echo" -Dexec.args='${project.version}' --non-recursive org.codehaus.mojo:exec-maven-plugin:1.5.0:exec | tail -1)
 echo "Building PMD Sonar ${VERSION} on branch ${TRAVIS_BRANCH}"
 
-if [ ! travis_isPush ]; then
+if ! travis_isPush; then
     echo "Not updating sonar, since this is not a push!"
     exit 0
 fi
diff --git a/.travis/common-functions.sh b/.travis/common-functions.sh
index 7c4c6b616b..6e9c9a8e26 100644
--- a/.travis/common-functions.sh
+++ b/.travis/common-functions.sh
@@ -14,16 +14,16 @@ echo "TRAVIS_ALLOW_FAILURE: $TRAVIS_ALLOW_FAILURE"
 
 function travis_isPullRequest() {
     if [ "$TRAVIS_PULL_REQUEST" != "false" ]; then
-        return true
+        return 0
     else
-        return false
+        return 1
     fi
 }
 
 function travis_isPush() {
     if [ "$TRAVIS_PULL_REQUEST" = "false" ] && [ "${TRAVIS_SECURE_ENV_VARS}" = "true" ]; then
-        return true
+        return 0
     else
-        return false
+        return 1
     fi
 }