composer.json

{
    "name": "mmollick/github-team-repos",
    "authors": [
        {
            "name": "Mike Mollick",
            "email": "[email protected]"
        }
    ],
    "require": {
        "guzzlehttp/guzzle": "^7.0"
    }
}

github.php

<?php

require_once __DIR__ . '/vendor/autoload.php';

// Create personal access token and place here
$access_token = '';

// Set organization name as it appears in the Github URLs
$org = '';

// Set team name as it appears in the Github URLs
$teamName = '';

$client = new \GuzzleHttp\Client([
    'base_uri' => 'https://api.github.com/resource'
]);

function request(string $method, string $url, array $params = []) : \Psr\Http\Message\ResponseInterface {
    global $access_token, $client;
    return $client->request($method, $url, [
        'query' => array_merge($params, [
            'access_token' => $access_token,
        ])
    ]);
}

// Get list of repositories from Github organization
$response = request('GET', "/orgs/${org}/repos", ['type' => 'all']);
$hasNextPage = str_contains($response->getHeader('Link')[0], 'next');
$repos = json_decode($response->getBody());
$page = 2;
while ($hasNextPage) {
    $response = request('GET', "/orgs/${org}/repos", ['page' => $page, 'type' => 'all']);
    $hasNextPage = str_contains($response->getHeader('Link')[0], 'next');
    $repos = array_merge($repos, json_decode($response->getBody()));
    $page++;
}

// Set access for each repo for the team. "permission" denotes what kind of access type they have, "pull" is read only
foreach ($repos as $repo) {
    fwrite(STDOUT, $repo->full_name . PHP_EOL);
    request('PUT', "/orgs/${org}/teams/${teamName}/repos/" . strtolower($repo->full_name), ['permission' => 'pull']);
}