Update local Git repositories in parallel, 1 thread per core

update_repos_routematch.sh

#!/bin/bash

export GIT_ROOT=/Volumes/Routematch/Git

doit() {
  cd $GIT_ROOT/$1
  # What branch is this repo on?
  # If master branch, checkout package.json and pull latest updates
  # If .nvmrc exists, use specified version, else use node version 4
  # Update dependencies
  # --no-save prevents npm from adding that pesky extra line break at end of package.json
  bash --login -c 'BRANCH=$(git rev-parse --abbrev-ref HEAD)
    if [[ "$BRANCH" == "master" ]]
    then
      [ -f package.json ] && git checkout package.json
      git pull
    fi

    if [ -f .nvmrc ]
    then
      nvm use
    else
      nvm use 4
    fi

    if [ -f package.json ]
    then
      npm install --no-save
    fi'
}

export -f doit

# Pull the latest scripts
cd $GIT_ROOT/com-utils-vagrant
git pull

cd $GIT_ROOT

# Add any missing development repos
com-utils-vagrant/gitutilities/createDeveloperGitClones.sh

# Update all the repos in parallel
if [[ $(command -v parallel) ]] ; then
  # use gnu parallel, if installed. Parallel defaults to 1 per core.
  ls -d1 */ | cut -d '/' -f1 | parallel -q --bar doit
else
  # Use core count
  CORES=$( sysctl -n hw.ncpu )
  ls -d1 */ | xargs -I % -n 1 -P $CORES doit
fi