allow drush user to perform a git pull at target

You might want to take a look at the Drush ssh command. What you want could nearly be done via:

drush @mysite.remoteserver ssh git pull

I say nearly because the Drush ssh command does not cd to the Drupal site root before running the requested command. If it did this, then I think that would be preferable to a custom command that did just a git pull.

You might also want to take a look at the file example/example.bashrc, which defines a function 'gitd' that is supposed to allow command such as:

gitd @mysite.remoteserver pull

This presently is not working, although the following workaround is:

drush @mysite.remoteserver ssh "cd /path/to/drupal/root; git pull"

The manual 'cd' is awkward, of course. I think it would be helpful to make the Drush ssh command insert the 'cd' at the head of the user command automatically. A patch that did this would be welcome in the Drush issue queue.

I wouldn't call them 'flaws'. It is perhaps a limitation to create a Drush command that will only execute a single git command ("pull"), but a remote git pull is still useful.

I fixed the 'gitd' command, so gitd @remote pull now works; the working version is now checked in to HEAD of Drush 8.x-6.x. The correct function looks like this:

function gitd() {
  s="$1"
  if [ -n "$s" ] && [ ${s:0:1} == "@" ] || [ ${s:0:1} == "%" ]
  then
    d="$(drush drupal-directory $s 2>/dev/null)"
    $(drush sa ${s%%:*} --component=remote-host > /dev/null 2>&1)
    if [ $? == 0 ]
    then
      drush ${s%%:*} ssh "cd '$d' ; git ${@:2}"
    else
      echo cd "$d" \; git "${@:2}"
      (
        cd "$d"
        "git" "${@:2}"
      )
    fi
  else
    "git" "$@"
  fi
}

I think this is about Drush and not Drush extras.

Sorry to reopen, but could this feature be extended to make easier pulling a contributed module?

See http://drupal.stackexchange.com/q/62934/10086

In 8.x-6.x-dev, the ssh command now automatically cd's to the Drupal root of the target, so you can now do this:

drush @site ssh git pull

Perhaps this can be considered fixed? If not, please be more specific with request. It is unlikely that we will do anything as specific as the example quoted in #6 in Drush core. Note also that this issue is originally about git pull, whereas the Stack Exchange question is about git clone.

Ok, makes sense.