Sync directory with an ID / name combination

sync.sh

#!/bin/sh

dir=${1-test}
mkdir -p $dir

rm -f $dir/updated
while read input ; do
  id=${input%=*}
  name=${input#*=}

  echo -n "#$id -> $name: "
  if [ -e $dir/.$id ] ; then
    current=$(readlink $dir/.$id)
    if [ "$current" != "$name" ] ; then
      echo -n "(renamed from $current): "
      mv $dir/$current $dir/$name
      ln -s -f $name $dir/.$id
    fi
  echo "OK"
  else
    echo "Creating..."
    mkdir -p $dir/$name
    ln -s $name $dir/.$id
  fi

  echo ".$id=$name" >> $dir/updated
done < test.map

# Find links not in updated file -> to be deleted
sort $dir/updated -o $dir/updated
find $dir -maxdepth 1 -type l -printf '%f=%l\n' | diff -u - $dir/updated | grep ^-.[0-9] | cut -d . -f2 > $dir/delete
while read input ; do
  id=${input%=*}
  name=${input#*=}

  echo "#$id -> $name: Deleting..."
  rm $dir/.$id
  mv $dir/$name $dir/.$id.deleted
done < $dir/delete

# Clean up
rm $dir/updated $dir/delete

echo ""
echo "@ $dir"
ls -Al $dir

test.map

1549=timm
1552=alex

Finally, remove the line with 1777 in it again:

$ sh sync.sh
#1549 -> timm: OK
#1552 -> alex: OK
#1777 -> dudette: Deleting...

@ test
total 2
lrwxrwxrwx  1 Timm Friebe None 4 Aug 20 22:06 .1549 -> timm
lrwxrwxrwx  1 Timm Friebe None 4 Aug 20 22:06 .1552 -> alex
drwxr-xr-x+ 1 Timm Friebe None 0 Aug 20 22:07 .1777.deleted
drwxr-xr-x+ 1 Timm Friebe None 0 Aug 20 22:06 alex
drwxr-xr-x+ 1 Timm Friebe None 0 Aug 20 22:06 timm