foreach: A repository from dtolnay

A setup for doing git operations across many repos using git submodule foreach.

$ git submodule foreach git fetch origin
$ git submodule foreach git checkout origin/master
$ sed -i s/…/…/ */*/.github/workflows/*.yml
$ git submodule foreach git commit -am "…"
$ git submodule foreach git push origin HEAD:master

The variables defined by git for the command are:

$name — name of the submodule section in .gitmodules. Here, this is set to the repo name, e.g. "syn".
$sm_path — path of the submodule as recorded in the superproject. This is the repo's user+name, e.g. "dtolnay/syn" or "serde-rs/json".
$displaypath — relative path from the current working directory to the submodule's root directory.
$sha1 — commit as recorded in the superproject.
$toplevel — absolute path to the top-level of the superproject: "/path/to/foreach".

Useful flags:

--quiet — Unless given --quiet, foreach prints the name of each submodule before evaluating the command.

A non-zero return from the command in any submodule causes the processing to terminate. This can be overridden by adding || : to the end of the command.

dtolnay/foreach