We have a large number of repositories maintained in our Github account. Is there a way to retrieve all repos which are defaulting and just have a master branch
You can write a script and check default branch. For example:
$ curl -s 'https://api.github.com/users/<username>/repos?per_page=1000' | grep 'default_branch'
"default_branch": "master"
# ..
# ..
# ..
This will print the default branch name. You can then filter out only relevant repos and have something like:
repos=$(...)
echo "$repos" | while read line ; do
git clone "$line"
done