A cron-managed script used for performing incremental backups.

rsync_backup.sh

#!/usr/bin/env bash
# Author: Danijel Milosevic
# No warranty, use at your own risk.

# How many snapshots to keep before starting to delete the old ones
SNAPSHOT_COUNT=15
# A list of absolute paths to backup.
INCLUDE_PATHS=("$HOME/Desktop/RSYNC/F1/")
# Overwrite if an arg was given
[ -z "$1" ] || INCLUDE_PATHS=$1

# Absolute path to transfer destination
TARGET_PATH="$HOME/Desktop/RSYNC/F2"
# Overwrite if an arg was given
[ -z "$2" ] || TARGET_PATH=$2

# A list of folder names and files to exclude.
EXCLUDE_PATHS=(
)

# Build proper rsync args from INCLUDE_PATHS array
for item in "${INCLUDE_PATHS[@]}"; do
  INCLUDE_ARGS="${INCLUDE_ARGS} ${item}"
done

# Build proper rsync args from EXCLUDE_PATHS array
for item in "${EXCLUDE_PATHS[@]}"; do
  EXCLUDE_FLAGS="${EXCLUDE_FLAGS} --exclude=${item}"
done

# Delete the oldest snapshot
if [ -d $TARGET_PATH.$SNAPSHOT_COUNT ]; then
  rm -rf $TARGET_PATH.$SNAPSHOT_COUNT
fi

# Rename existing snapshots 1 number higher
for (( i=$SNAPSHOT_COUNT; i>0; i-- )); do
  if [ -d $TARGET_PATH.$(($i - 1)) ]; then
    mv $TARGET_PATH.$(($i - 1)) $TARGET_PATH.$i
    # Special case for the latest backup dir, since it doesn't have a digit appended
  elif [ $i -eq 1 ] && [ -d $TARGET_PATH ]; then
    mv $TARGET_PATH $TARGET_PATH.$i
  fi
done

# If a backup exists, save disk space by utilising hard links to existing files if they are identical as the new backup
if [ -d $TARGET_PATH.1 ]; then
  RSYNC_ARGS=( --link-dest="$TARGET_PATH.1")
fi;
RSYNC_ARGS+=(
    --recursive # Copy everything from subdirs
    --links     # Copy over symlinks
    --hard-links  # Copy over hard links
    --perms     # Preserve user perms
    --times     # Preserve time stamps
    --group     # Preserve file group
    --checksum  # Skips files based on checksum instead of datetime + size comparison. Better but slower
    --owner     # Preserve file owner
    -D          # Transfer special files like socket, device
    --progress  # Show transfer progress
    #--partial   # Keep partially transfered files
    --update    # Skip files that are newer on the receiver
    --human-readable  # Makes the transfer output more readable
    #--relative  # Use relative path names
    --compress  # Compress/decompress during transfer. Useful over network
    --delete    # Delete files in destination that don't exist in source
    --log-file=$HOME/rsync.log  # Store the logs in the home dir
    #--dry-run  # Disables rsync, just shows what would have been copied instead. Good for testing/debugging
    ${EXCLUDE_FLAGS}  # Transfer blacklist
    ${INCLUDE_ARGS}   # List of source directories
    $TARGET_PATH      # Target directory
)
rsync "${RSYNC_ARGS[@]}"  # Actual execution