allrepos.py: get stuff done with 100x git repo directories

Utility for working with multiple repos when repos have been placed in a single top level dir

Couple of example use cases

Run fetch for all

python allrepos.py fetch

Get default branches

python allrepos.py symbolic-ref refs/remotes/origin/HEAD | sed 's@^refs/remotes/origin/@ @'

Delete all branches with name foo from remotes:

python allrepos.py ls-remote --exit-code --heads origin foo IF_OK_EXECUTE_ALSO push origin --delete foo

Requirements

• Python 3.6+ since uses f-strings.
• Git.

Note: the examples here involve usage of unix tools, but this is not limited to unix.