Used to update hard links based on a file called links. Requires hlink and hulink. I'm using this to put the music I want to sync to my phone into a specific directory, as BitTorrent Sync does not follow symlinks.

gistfile1.sh

#!/bin/bash

cd "/Volumes/Marceline/MusicSync/"

# first unlink files which have been removed
for artist in *; do
    if [ -d "$artist" ]; then
      if ! grep -Fxq "$artist" "links" ; then
        echo Unlinking $artist
        hulink "$artist"
      fi
    fi
done

# link any new ones
while read artist; do
  if [ ! -d "$artist" ]; then
    echo Linking $artist
    hlink "../Music/$artist" "$artist"
  fi
done < links