Simple kubectl declarative version updater

kubectl_update.sh

#!/bin/bash

# Updates kubectl in the ~/bin directory. Provide a base version number, like
# "1.20", and this will find the latest patch release, download it, verify the
# hash, and overwrite the kubectl in ~/bin.
# Usage: update_kubectl <base version number>
update_kubectl() {
  if [[ $# -eq 0 ]]; then
    echo 'Missing base version, such as "1.20".'
  else
    mkdir -p ~/bin
    K_REPO="https://api.github.com/repos/kubernetes/kubernetes/releases?per_page=100"
    REQ_VER=$(curl --silent -H "Accept: application/vnd.github.v3+json" $K_REPO | jq -r '.[].tag_name' | grep -v alpha | grep -v beta | grep -v rc | grep "v$1" | head -n1)
    echo "Found version $REQ_VER."
    cd /tmp && \
      curl --silent -LO "https://dl.k8s.io/release/$REQ_VER/bin/darwin/amd64/kubectl" && \
      curl --silent -LO "https://dl.k8s.io/release/$REQ_VER/bin/darwin/amd64/kubectl.sha256" && \
      echo "$(<kubectl.sha256)  kubectl" | shasum -a 256 --check && \
      chmod a+x kubectl && \
      cp kubectl ~/bin/kubectl
    kubectl version --client
  fi
}