version switcher for kubectl, kops, helm and terraform - requires https://github.com/junegunn/fzf

.bashrc

function versionswitcher {
    local BINARY="$1"
    local URL="$2" #must contain 'VERSION' in it somewhere to enable download of different versions
    local CACHE="${HOME}/.${BINARY}.versions"
    local DSTFILE="/usr/local/bin/${BINARY}"
    local TEMPDIR="${CACHE}/tmp"

    mkdir -p "$CACHE"

    if [[ ! "$3" ]]; then 
        local VERSION=$(ls "$CACHE" | fzf)
        if [[ "$VERSION" == "" ]]; then return 1; fi
        local SRCFILE="${CACHE}/${VERSION}"
    else
        local VERSION="$3"
        local SRCFILE="${CACHE}/${BINARY}_${VERSION}"
    fi    
    
    if ! [ -f "$SRCFILE" ]; then
        echo "not found - downloading ${VERSION} of ${BINARY}..."
        curl -L --fail --silent "${URL//VERSION/$VERSION}" -o "$SRCFILE"
        if [ $? -ne "0" ] ; then
            echo "error downloading ${VERSION} of ${BINARY} - aborting"
            return 1
        fi
        if [[ "$URL" == *.tar.gz || "$URL" == *.zip ]]; then
            mkdir -p "$TEMPDIR"
            tar -xf "$SRCFILE" -C "$TEMPDIR" || unzip "$SRCFILE" -d "$TEMPDIR"
            mv -f "$(find "$TEMPDIR" -type f -name "$BINARY")" "$SRCFILE"
            rm -rf "$TEMPDIR"
        fi
        chmod +x "$SRCFILE"
    fi

    if [ -L "$DSTFILE" ]; then
        unlink "$DSTFILE"
    fi
    echo "setting ${BINARY} to ${VERSION}"
    ln -s "$SRCFILE" "$DSTFILE"
}
function gethelm {
    versionswitcher "helm" "https://get.helm.sh/helm-VERSION-darwin-amd64.tar.gz" "$1"
}
function getkops {
    versionswitcher "kops" "https://github.com/kubernetes/kops/releases/download/VERSION/kops-darwin-amd64" "$1"
}
function getkubectl {
    versionswitcher "kubectl" "https://storage.googleapis.com/kubernetes-release/release/VERSION/bin/darwin/amd64/kubectl" "$1"
}

function gettf {
    versionswitcher "terraform" "https://releases.hashicorp.com/terraform/VERSION/terraform_VERSION_darwin_amd64.zip" "$1"
}