increment_tag.sh

#!/bin/bash -e

#based on: https://stackoverflow.com/a/27332476/2777965

#get highest tag number
VERSION=`git describe --abbrev=0 --tags`

#replace . with space so can split into an array
VERSION_BITS=(${VERSION//./ })

#get number parts and increase last one by 1
VNUM1=${VERSION_BITS[0]}
VNUM2=${VERSION_BITS[1]}
VNUM3=${VERSION_BITS[2]}
VNUM3=$((VNUM3+1))

#create new tag
NEW_TAG="$VNUM1.$VNUM2.$VNUM3"

echo "Updating $VERSION to $NEW_TAG"

LATEST_TAG=$(git tag | tail -1)
TAG_COMMIT=$(git rev-list -n 1 $LATEST_TAG)
echo $TAG_COMMIT
LATEST_COMMIT=$(git rev-parse HEAD)
echo $LATEST_COMMIT

if [ "${LATEST_COMMIT}" != "${TAG_COMMIT}" ]; then
    echo "Tagged with $NEW_TAG (Ignoring fatal:cannot describe - this means commit is untagged) "
    git tag $NEW_TAG
    git push --tags
else
    echo "Already a tag on this commit"
fi