Tuesday, 4 July 2017

Mac OS - Check Java version before running script

I needed to check what version of Java was installed on a Mac before running my program, so with the help of stackoverflow and a few other resources I pulled together the following bash script which checks to see if the version of Java is greater than 1.8 before continuing.
# Work out the JAVA version we are working with:
JAVA_VER_MAJOR=""
JAVA_VER_MINOR=""
JAVA_VER_BUILD=""

# Based on: http://stackoverflow.com/a/32026447
for token in $(java -version 2>&1 | grep -i version)
do
    if [[ $token =~ \"([[:digit:]])\.([[:digit:]])\.(.*)\" ]]
    then
        JAVA_VER_MAJOR=${BASH_REMATCH[1]}
        JAVA_VER_MINOR=${BASH_REMATCH[2]}
        JAVA_VER_BUILD=${BASH_REMATCH[3]}
        break
    fi
done

#check version is greater than 1.7 (i.e. at least 1.8)
if [ "$JAVA_VER_MAJOR" -gt "1" ]; then
    echo start your program
elif [ "$JAVA_VER_MINOR" -gt "7" ]; then
    echo start your program
else
    echo ERROR - Java needs to be updated.
    echo Currently installed version is $JAVA_VER_MAJOR.$JAVA_VER_MINOR - 1.8 is required
fi

2 comments:

  1. thank you for updating us with this post. it really helps me out of a few issues that i need to deal with since your way seems to be much safer

    ReplyDelete