git-tracks

#!/bin/bash
#
# Get the upstream branch for the current branch.  If -d/--default is passed,
# outputs origin/master if there's no upstream branch.
#
# To set <branch>'s upstream branch, run
#
#   $ git branch --set-upstream <branch> <upstream>
#
#
# Based on http://serverfault.com/a/352236/38694

branch=$(git symbolic-ref HEAD) || exit $?
branch=${branch##refs/heads/}
remote=$(git config "branch.${branch}.remote" || echo '.')
remoteBranch=$(git config "branch.${branch}.merge" || echo '')
remoteBranch=${remoteBranch##refs/heads/}

if [[ "$remote" != "." ]]; then
  echo "${remote:?}/${remoteBranch:?}"
elif [[ "$remoteBranch" != "" ]]; then
  echo "${remoteBranch:?}"
elif [[ "$1" == '-d' || "$1" == '--default' ]]; then
  echo "origin/master"
fi