Semver with Git and Bash

cm-version.sh

V=$(git describe --tags --abbrev=0)
Y=$(date +"%Y")
m=$(date +"%m")
d=$(date +"%d")
today="$(date +"%Y")$(date +"%m")$(date +"%d")"
verregex="([0-9]+)"
preregex="([0-9]{8})\.([0-9]+)"
bldregex="(\+[a-zA-Z]+)?"
regex="^v$verregex\.$verregex\.$verregex-$preregex$bldregex$"
if [[ $V =~ $regex ]]
then
    major="${BASH_REMATCH[1]}"
    minor="${BASH_REMATCH[2]}"
    patch="${BASH_REMATCH[3]}"
    stamp="${BASH_REMATCH[4]}"
    frank="${BASH_REMATCH[5]}"
    echo "Most recent version: $V"
    echo "Major: $major | Minor:  $minor | Patch: $patch | Stamp: $stamp | Frank: $frank"
    if [[ "$stamp" == "$today" ]]
    then
        frank="$(($frank + 1))"
        echo "There was a commit earlier today: updating frank to $frank"
    else
        stamp="$today"
        frank=0
        echo "First commit today... starting frank at 0"
    fi
    if [ $# -eq 0 ];
    then
        echo "Updating tag/version with date only."       
        echo "Today is: $today"
    else
        if [[ "$1" == "patch" || "$1" == "minor" || "$1" == "major" ]]
        then
            echo "Updating $1 version in tag. Currently at ${!1}"
            declare $1="$((${!1} + 1))"
            echo "Will change $1 version to ${!1}"
            if [[ "$1" == "minor" ]]
            then
                patch=0
            elif [[ "$1" == "major" ]]
            then
                patch=0
                minor=0
            fi
        fi
    fi
    echo "Now updated version: v$major.$minor.$patch-$stamp.$frank"
else
    echo "The format of the previous Git tag doesn't look right..."
fi