creating tag with version for deploying purposes

version_tag.sh

function version_tag() {
    # Script automatically increments revision in REVISION file.
    # Creates tag and pushes it to git origin for deploy.
    if [ ! -d .git ]; then
        echo "not a git repo"
        return
    fi

    if [ ! -f REVISION ]; then
        # create REVISION file with zero version
        echo "v0.0.0" > REVISION
    fi

    rev=$(<REVISION);
    new_rev=$(echo "$rev" | awk -F. -v OFS=. 'NF==1{print ++$NF}; NF>1{if(length($NF+1)>length($NF))$(NF-1)++; $NF=sprintf("%0*d", length($NF), ($NF+1)%(10^length($NF))); print}');
    echo "New version is $new_rev";
    echo "$new_rev" > REVISION;
    git add REVISION
    git commit REVISION -m "Revision updated $new_rev";
    git tag -a $new_rev -m "Deploy tag $new_rev";
    git push origin master;
    git push origin $new_rev;
}