rsync A->B - Transfer a directory from a source server (A) into a directory on a target server (B) via SSH & rsync

rsyncAB.sh

#!/usr/bin/env bash

# This script will transfer a directory from a source server (A)
# into a directory on a target server (B)
# Pre-requisites: The script must be run by a user who has SSH / passwordless access to both server A & B

# From StackExchange.com (https://unix.stackexchange.com/a/317815) - Authored by David I. (https://unix.stackexchange.com/users/71948/david-i) adapated from an answer by roaima (https://unix.stackexchange.com/users/100397/roaima) - Under the license: cc by-sa 4.0 with attribution required (https://creativecommons.org/licenses/by-sa/4.0/)
# Slight modifications may have been made to the original script, which are in no way endorsed by the original authors of this script
# Specific alterations include:
# - the rsync parameters checking files by checksum instead of date/time/size
# - no strict key checking in SSH, so make sure you're connecting to trusted servers!
# - verbosity settings are turned on both for SSH and rsync to help in debugging issues
# - Making the input parameters configurable and required before the script begins

# This script is for my personal use only, by using it you do so at your own risk

if [[ "$1" ]]; then
  SOURCE_USER="$1"
else
  echo "Please enter a source user, usually before the @ within an ssh command"
  exit 1
fi

if [[ "$2" ]]; then
  SOURCE_HOST="$2"
else
  echo "Please enter a source host, usually after the @ in an ssh command"
  exit 1
fi

if [[ "$3" ]]; then
  SOURCE_PATH="$3"
else
  echo "Please enter a source path, usually starting with a forward slash /"
  exit 1
fi

if [[ "$4" ]]; then
  TARGET_USER="$4"
else
  echo "Please enter a target user, usually before the @ within an ssh command"
  exit 1
fi

if [[ "$5" ]]; then
  TARGET_HOST="$5"
else
  echo "Please enter a target host, usually after the @ in an ssh command"
  exit 1
fi

if [[ "$6" ]]; then
  TARGET_PATH="$6"
else
  echo "Please enter a target path, usually starting with a forward slash /"
  exit 1
fi

ssh -o StrictHostKeyChecking=no -v -l $TARGET_USER -A -R localhost:22000:$TARGET_HOST:22 \
  $SOURCE_USER@$SOURCE_HOST "rsync -e 'ssh -o StrictHostKeyChecking=no -v -p 22000' -arvz --checksum --delete --progress --stats $SOURCE_PATH \
$TARGET_USER@localhost:$TARGET_PATH"