Error: "git: 'submodule' is not a git command" on Intel Edison and git 2.0.1

Yes, the Git on Edison might be a light weight version. As mentioned by msw in the comments, the best option is to build git from source. But I believe the next version of Yocto package might come with a new version of git.

It appears when building git with Yocto the behavior is as intended. Unfortunately the intended behavior is not what you would expect. On Ubuntu, git-submodule is included in the package git, on Yocto in package git-perltools. When you run bitbake git the following packages are built (Thud):

ferry@delfion:~/.../out/linux64/build/tmp/work/corei7-32-poky-linux/git/2.18.1-r0/deploy-debs/corei7-32$ ls -l
- git_2.18.1-r0_i386.deb
- git-bash-completion_2.18.1-r0_i386.deb
- git-dbg_2.18.1-r0_i386.deb
- git-dev_2.18.1-r0_i386.deb
- git-doc_2.18.1-r0_i386.deb
- git-perltools_2.18.1-r0_i386.deb
- gitweb_2.18.1-r0_i386.deb

with git-perltools containing git-submodule.

How could you know in advance? Checkout https://layers.openembedded.org. You can easily find: http://cgit.openembedded.org/openembedded-core/tree/meta/recipes-devtools/git/git.inc?h=thud, which contains:

PERLTOOLS = " \
    ${libexecdir}/git-core/git-add--interactive \
    ${libexecdir}/git-core/git-archimport \
    ${libexecdir}/git-core/git-cvsexportcommit \
    ${libexecdir}/git-core/git-cvsimport \
    ${libexecdir}/git-core/git-cvsserver \
    ${bindir}/git-cvsserver \
    ${libexecdir}/git-core/git-difftool \
    ${libexecdir}/git-core/git-send-email \
    ${libexecdir}/git-core/git-svn \
    ${libexecdir}/git-core/git-instaweb \
    ${libexecdir}/git-core/git-submodule \
    ${libexecdir}/git-core/git-am \
    ${libexecdir}/git-core/git-request-pull \
    ${datadir}/gitweb/gitweb.cgi \
    ${datadir}/git-core/templates/hooks/prepare-commit-msg.sample \
    ${datadir}/git-core/templates/hooks/pre-rebase.sample \
    ${datadir}/git-core/templates/hooks/fsmonitor-watchman.sample \
"

# Git tools requiring perl
PACKAGES =+ "${PN}-perltools"
FILES_${PN}-perltools += " \
    ${PERLTOOLS} \
    ${libdir}/perl \
    ${datadir}/perl5 \
"

So adding not only git, but also git-perltools to your core-image will get you what you want + a bit more.

OTOH Yocto has a nice feature that builds you a cross-compiler environment on your host. So you can configure to use f.i. QT Creator to build using the sdk and remote debug the target from your host. That way you don't need to build/install your toolchain on the Intel Edison. More on this here: https://edison-fw.github.io/meta-intel-edison/3-Building-the-SDK.html

Ferry Toth (aka htot@github)

The question is old but as I fell on the same problem on Edison board is here my workaround, it may still interest some people.
The yocto version I am using for Edison is this one: https://github.com/edison-fw/meta-intel-edison

The problem happens because the git version on Edison board is missing some parts. In this case the git-submodules binary is missing in /usr/libexec/git-core

So once you have built the yocto image following the explanations you can find on the same link above (or here https://edison-fw.github.io/meta-intel-edison/) and flashed your board, you will have to copy the file git-submodules from your host pc to your edison board.

On your host, once in your build directory (path/to/edison/out/linux64/build), type:

find . -name "git-submodule"

And you will get different locations for the same file. Take one of it.

Copy it on the edison board to /usr/libexec/git-core.

Now the git with submodule should hopefully work...

---

UPDATE:
Ferry answer is better but in someways it does not work on my side (yocto sumo). Package git-perltools is part of git package, so no need to add it to your core-image, but it is still not installed. I found that package git-perltools depends on findutils to be installed, so adding findutils to core-image might be needed for Ferry's answer to work.

NB:
I would have preferred to comment Ferry answer, but I don't have the rights.