A script for updating an existing Gradle wrapper in a given directory to another version.

update_gradle_wrapper.sh

#!/usr/bin/env sh

if [ $# -ne 2 ]; then
  echo "This script needs exactly two parameters: the path where the current Gradle wrapper is and the version to which to upgrade."
  echo "Example: ./update_gradle_wrapper.sh ./path/to/directory/to/update/ 1.2.3"
  exit 1;
fi

distType="all"
path="$1"
version="$2"

cd "$path"
# Execute 2 times, so the wrapper task is executed by the specified Gradle version (the first time the "old" version is used).
# Additionally this makes sure, that the specified Gradle version is downloaded and cached.
for i in 0 1; do
  ./gradlew wrapper --gradle-version="$version" --distribution-type="$distType"
done

# Remove comments
sed -i -e '/^#.*/d' gradle/wrapper/gradle-wrapper.properties

# Add SHA256 sum
shaSum=`sha256sum ~/.gradle/wrapper/dists/gradle-$version-$distType/*/gradle-$version-$distType.zip | cut -c 1-64`
printf "distributionSha256Sum=$shaSum" >> gradle/wrapper/gradle-wrapper.properties