sync-remote-file

#!/usr/bin/env bash
#
# The `sync-remote-file` is designed to synchronize local and remote files. The
# user can specify the direction of the sync (i.e., whether files are
# transferred from local to remote or remote to local), or can decide at runtime
# when prompted if differences are found.
#
# It accepts an optional argument -d to specify the direction of the sync:
#
#   R: sync local file to remote.
#   L: sync remote file to local.
#
# Usage:
#   sync-remote-file [-d <L|R>] <local-file-path> <remote-file-path>
#
# Example:
#   sync-remote-file ./bin/build-cli [email protected]:/mnt/test/usr/local/buildbox/bin/build-cli
#
# by @allex_wang
# Released under the MIT License.
#
# GistID: 5dd8c160752333dc041cd5a222c06a1e
# GistURL: https://gist.github.com/5dd8c160752333dc041cd5a222c06a1e

sync-remote-file() {
  local sync_direction
  local OPTIND opt

  while getopts ":d:" opt; do
    case "${opt}" in
      d)
        sync_direction=${OPTARG}
        ;;
      \?)
        echo "Invalid Option: -$OPTARG" 1>&2
        return 1
        ;;
      :)
        echo "Option -$OPTARG requires an argument." 1>&2
        return 1
        ;;
    esac
  done
  shift $((OPTIND -1))

  if [ $# -ne 2 ]; then
    echo "Usage: sync-remote-file [-d <sync-direction,L|R>] <local-file-path> <remote-file-path>"
    return 1
  fi

  local_file="$1"
  remote_path="$2"

  user_host="${remote_path%%:*}"
  remote_file="${remote_path#*:}"

  if [ -n "$sync_direction" ] && [ "$sync_direction" != "L" ] && [ "$sync_direction" != "R" ]; then
    echo >&2 "fatal: invalid sync direction: [$sync_direction]. Please use either [L] for remote-to-local' or [R] for local-to-remote'"
    return 1
  fi

  # shellcheck disable=SC2029
  # Compare the local and remote files in patch diff format
  diff_output=$(diff -u <(command ssh "$user_host" cat "$remote_file") "$local_file")

  if [ -n "$diff_output" ]; then
    # Show the diff and prompt the user to sync
    echo "Differences found between local and remote files:"
    echo "$diff_output"

    if [ -z "$sync_direction" ]; then
      read -r -p "Choose the sync action (N to cancel, L for remote-to-local, R for local-to-remote): " choice
    else
      choice=$sync_direction
    fi

    case "$choice" in
      R|r )
        # Copy the local file to the remote host
        scp -p "$local_file" "$user_host:$remote_file"
        echo "Local file synchronized to remote file."
        ;;
      L|l )
        # Copy the remote file to the local host
        scp -p "$user_host:$remote_file" "$local_file"
        echo "Remote file synchronized to local file."
        ;;
      N|n|"" )
        echo "No changes will be made."
        ;;
      * )
        echo >&2 "fatal: invalid sync operator '$choice', no changes will be made."
        return 1
        ;;
    esac
  else
    echo "Local and remote files are already in sync."
  fi
}

sync-remote-file "$@"