Bash script to pull github organizations. Note '-C' for git requires a modern git version.

github-cloner.sh

#!/bin/bash

# you PROBABLY want to use an ssh-key for this, or you'll
# be typing your password over and over and over...

# you MUST set ORG_NAME and ACCESS_TOKEN below!
# if you want to grab private repositories, the
# token must have the full "repos" scope selected
# 
# ... note no other scopes are required, and you
#     should take care to guard this token!
#
# https://github.com/settings/tokens

SELFCMD="${0}"
SELFNAME="$(basename "${SELFCMD}")"
ORG_NAME="" # SET ME! See comments above!
ACCESS_TOKEN="" # SET ME! See comments above!
GITHUB_INSTANCE="api.github.com" # enterprise accounts may need to adjust
PAGE="1"
PERPAGE="30" # max 100 per github API, default 30

if [ "${#}" -eq 1 ]; then
  function checkint()
  {
    printf "%d" "${1}" &>/dev/null
    return "${?}"
  }
  if checkint "${1}"; then
    PAGE="${1}"
  else
    >&2 echo "(${SELFNAME}) Invalid argument. Provide no arguments (or optionally an API page number greater than or equal to 1)."
    exit 1
  fi
fi

URL="https://${GITHUB_INSTANCE}/orgs/${ORG_NAME}/repos?per_page=${PERPAGE}&page=${PAGE}"

echo "(${SELFNAME}) requesting" "${URL}"
REPOLIST="$(curl -s -H "Authorization: token ${ACCESS_TOKEN}" "${URL}" | grep '"ssh_url"' | cut -d '"' -f 4)"

if (( ${#REPOLIST} > 0 )); then
  for REPO in ${REPOLIST}; do
    REPOFILE="$(echo "${REPO}" | awk -F '/' '{print $NF}')"
    REPODIR="${REPOFILE%.git}"
    if ! [ -x ./"$REPODIR" ]; then
      echo "Cloning: ${REPO} (into ${REPODIR})"
      git clone "${REPO}" "${REPODIR}"
      for branch in $(git -C "${REPODIR}" branch --all | grep '^\s*remotes' | grep -E --invert-match '(:?HEAD|master|main)$'); do
        echo "Tracking: ${REPO} / ${branch}"
        git -C "${REPODIR}" branch --track "${branch##*/}" "$branch"
      done
    fi
      echo "Pulling: ${REPODIR}"
      git -C "${REPODIR}" fetch --all --prune || echo "GIT FETCH FAILED FOR: ${REPODIR}" | tee cloner-fails.log
      git -C "${REPODIR}" gc --auto || echo "GIT GC FAILED FOR: ${REPODIR}" | tee -a cloner-fails.log
      git -C "${REPODIR}" pull || echo "GIT PULL FAILED FOR: ${REPODIR}" | tee -a cloner-fails.log
    unset REPOFILE
    unset REPODIR
  done
else
  echo "(${SELFNAME}) received 0 repostory URLs - process completed or something went wrong."
  exit 0
fi

if [ ${#REPOLIST} -ge ${PERPAGE} ]; then
  echo "(${SELFNAME}) recursing with PAGE=${PAGE}"
  exec "${SELFCMD}" $(( ${PAGE} + 1 ))
fi