Reorder borg (borgbackup) segments if core repository config segments_per_dir was changed

borg-migrate-segments.sh

#!/bin/sh

if [ -z "$BORG_REPO" ]; then
  echo "BORG_REPO not set. Export variable like:"
  echo "export BORG_REPO=/mnt/borg"
  exit 1
fi
BORG_REPO=$(readlink -f "$BORG_REPO")
if [ ! -e "$BORG_REPO/config" ]; then
  echo "Invalid BORG_REPO dir: $BORG_REPO"
  exit 1
fi

SEGMENTS_PER_DIR=$(cat "$BORG_REPO/config" | grep segments_per_dir | sed 's/\s//g' | cut -d'=' -f2)
if [ -z "$SEGMENTS_PER_DIR" -o "$SEGMENTS_PER_DIR" -le 0 ]; then
  echo "Could not read segments_per_dir"
  exit 1
fi
echo "Migrating borg repository $BORG_REPO with $SEGMENTS_PER_DIR segments per dir"

DATA_DIR="$BORG_REPO/data";
find "$DATA_DIR" -type f | while read SEGMENT; do 
  SEGMENT_ID=$(basename $SEGMENT)
  ORIG_DIR=$(basename $(dirname $SEGMENT)) 
  DIR=$(($SEGMENT_ID / $SEGMENTS_PER_DIR)) 

  if [ "$ORIG_DIR" != "$DIR" ]; then
    if [ ! -d "$DATA_DIR/$DIR" ]; then
      mkdir "$DATA_DIR/$DIR"
    fi

    echo "Move segment $ORIG_DIR/$SEGMENT_ID -> $DIR/$SEGMENT_ID"
    mv "$DATA_DIR/$ORIG_DIR/$SEGMENT_ID" "$DATA_DIR/$DIR/$SEGMENT_ID"
  fi
done