[git] List submodules in a Git repository

In my version of Git [1], every Git submodule has a name and a path. They don't necessarily have to be the same [2]. Getting both in a reliable way, without checking out the submodules first (git update --init), is a tricky bit of shell wizardry.

Get a list of submodule names

I didn't find a way how to achieve this using git config or any other git command. Therefore we are back to regex on .gitmodules (super ugly). But it seems to be somewhat safe since git limits the possible code space allowed for submodule names. In addition, since you probably want to use this list for further shell processing, the solution below separate entries with NULL-bytes (\0).

$ sed -nre \
  's/^\[submodule \"(.*)\"]$/\1\x0/p' \
  "$(git rev-parse --show-toplevel)/.gitmodules" \
| tr -d '\n' \
| xargs -0 -n1 printf "%b\0"

And in your script:

#!/usr/bin/env bash

while IFS= read -rd '' submodule_name; do
  echo submodule name: "${submodule_name}"
done < <(
  sed -nre \
    's/^\[submodule \"(.*)\"]$/\1\x0/p' \
    "$(git rev-parse --show-toplevel)/.gitmodules" \
  | tr -d '\n' \
  | xargs -0 -n1 printf "%b\0"
)

Note: read -rd '' requires bash and won't work with sh.

Get a list of submodule paths

In my approach I try not to process the output from git config --get-regexp with awk, tr, sed, ... but instead pass it a zero byte separated back to git config --get. This is to avoid problems with newlines, spaces and other special characters (e.g. Unicode) in the submodule paths. In addition, since you probably want to use this list for further shell processing, the solution below separate entries with NULL-bytes (\0).

$ git config --null --file .gitmodules --name-only --get-regexp '\.path$' \
| xargs -0 -n1 git config --null --file .gitmodules --get

For example, in a Bash script you could then:

#!/usr/bin/env bash

while IFS= read -rd '' submodule_path; do
  echo submodule path: "${submodule_path}"
done < <(
  git config --null --file .gitmodules --name-only --get-regexp '\.path$' \
  | xargs -0 -n1 git config --null --file .gitmodules --get
)

Note: read -rd '' requires bash and won't work with sh.


Footnotes

[1] Git version

$ git --version
git version 2.22.0

[2] Submodule with diverging name and path

Set up test repository:

$ git init test-name-path
$ cd test-name-path/
$ git checkout -b master
$ git commit --allow-empty -m 'test'
$ git submodule add ./ submodule-name
Cloning into '/tmp/test-name-path/submodule-name'...
done.
$ ls
submodule-name

$ cat .gitmodules
[submodule "submodule-name"]
    path = submodule-name
    url = ./

Move submodule to make name and path diverge:

$ git mv submodule-name/ submodule-path

$ ls
submodule-path

$ cat .gitmodules
[submodule "submodule-name"]
    path = submodule-path
    url = ./

$ git config --file .gitmodules --get-regexp '\.path$'
submodule.submodule-name.path submodule-path

Testing

Set up test repository:

$ git init test
$ cd test/
$ git checkout -b master
$ git commit --allow-empty -m 'test'
$
$ git submodule add ./ simplename
Cloning into '/tmp/test/simplename'...
done.
$
$ git submodule add ./ 'name with spaces'
Cloning into '/tmp/test/name with spaces'...
done.
$
$ git submodule add ./ 'future-name-with-newlines'
Cloning into '/tmp/test/future-name-with-newlines'...
done.
$ git mv future-name-with-newlines/ 'name
> with
> newlines'
$
$ git submodule add ./ 'name-with-unicode-'
Cloning into '/tmp/test/name-with-unicode-'...
done.
$
$ git submodule add ./ sub/folder/submodule
Cloning into '/tmp/test/sub/folder/submodule'...
done.
$
$ git submodule add ./ name.with.dots
Cloning into '/tmp/test/name.with.dots'...
done.
$
$ git submodule add ./ 'name"with"double"quotes'
Cloning into '/tmp/test/name"with"double"quotes'...
done.
$
$ git submodule add ./ "name'with'single'quotes"
Cloning into '/tmp/test/name'with'single'quotes''...
done.
$ git submodule add ./ 'name]with[brackets'
Cloning into '/tmp/test/name]with[brackets'...
done.
$ git submodule add ./ 'name-with-.path'
Cloning into '/tmp/test/name-with-.path'...
done.

.gitmodules:

[submodule "simplename"]
    path = simplename
    url = ./
[submodule "name with spaces"]
    path = name with spaces
    url = ./
[submodule "future-name-with-newlines"]
    path = name\nwith\nnewlines
    url = ./
[submodule "name-with-unicode-"]
    path = name-with-unicode-
    url = ./
[submodule "sub/folder/submodule"]
    path = sub/folder/submodule
    url = ./
[submodule "name.with.dots"]
    path = name.with.dots
    url = ./
[submodule "name\"with\"double\"quotes"]
    path = name\"with\"double\"quotes
    url = ./
[submodule "name'with'single'quotes"]
    path = name'with'single'quotes
    url = ./
[submodule "name]with[brackets"]
    path = name]with[brackets
    url = ./
[submodule "name-with-.path"]
    path = name-with-.path
    url = ./

Get list of submodule names

$ sed -nre \
  's/^\[submodule \"(.*)\"]$/\1\x0/p' \
  "$(git rev-parse --show-toplevel)/.gitmodules" \
| tr -d '\n' \
| xargs -0 -n1 printf "%b\0" \
| xargs -0 -n1 echo submodule name:
submodule name: simplename
submodule name: name with spaces
submodule name: future-name-with-newlines
submodule name: name-with-unicode-
submodule name: sub/folder/submodule
submodule name: name.with.dots
submodule name: name"with"double"quotes
submodule name: name'with'single'quotes
submodule name: name]with[brackets
submodule name: name-with-.path

Get list of submodule paths

$ git config --null --file .gitmodules --name-only --get-regexp '\.path$' \
| xargs -0 -n1 git config --null --file .gitmodules --get \
| xargs -0 -n1 echo submodule path:
submodule path: simplename
submodule path: name with spaces
submodule path: name
with
newlines
submodule path: name-with-unicode-
submodule path: sub/folder/submodule
submodule path: name.with.dots
submodule path: name"with"double"quotes
submodule path: name'with'single'quotes
submodule path: name]with[brackets
submodule path: name-with-.path