Clone or pull multiple git repos from specific branches based on a JSON input file

gitget.sh

#!/bin/bash

set -e

# This command reads the file repos.json and clones or pulls
# git repositories in particular branches. If there are local
# edits in these repos, they are stashed and reapplied.
#
# Credits:
# 1. https://stackoverflow.com/questions/6550484/prevent-grep-returning-an-error-when-input-doesnt-match
# 2. https://stackoverflow.com/questions/34114700/git-stash-pop-only-if-successfully-stashed-before
# 
# Prerequisites:
# 1. Install 'jc' command
#
# The file repos.json looks like:
# [
#  {
#    "name": "foo",
#    "repo": "git@github.com:org/foo.git",
#    "branch": "master"
#  },
#  {
#    "name": "bar",
#    "repo": "git@github.com:org/bar.git",
#    "branch": "master"
#  },
# ]
#
# The name key must contain the name of the repository without
# the .git extension (extra credit to use sed to do
# this for you)

# create a unique timestamp for the stash name
t=timestamp-$(date +%s) 

for row in $(jq -c '.[]' repos.json); do
  _jq() {
    echo ${row} |  jq -r ${1}
  }

  NAME=$(_jq '.name')
  REPO=$(_jq '.repo')
  BRANCH=$(_jq '.branch')

  echo
  echo "*** $NAME ***"

  if [ -d $NAME ]; then
    cd $NAME

    git fetch

    # stash with message
    r=$(git stash save -u $t)

    git checkout $BRANCH
    git pull

    # if the stash was created above, reapply it
    v=$(echo $r | grep $t | { grep -v grep || test $? = 1; })
    if [ "$v" ]; then 
      git stash pop
    fi
    cd ..
  else
    git clone -b $BRANCH $REPO
  fi
done