Rsync and a lock file: flock

flockRsyncBackup.sh

#!/bin/bash

# Example of flock use with rsync where local files are pushed to a remote server using a ssh and a key.
# Using flock is useful when file copying is slow and the transfer duration may overlap with a newly scheduled run.
# For example, if a large number of files are uploaded in one day in an office, whose backup is scheduled every day, and the transfer may take more than 24 hours.

# Flock use a lock file: if it already exist it does not execute the command (-n option)
# Read more on https://www.man7.org/linux/man-pages/man1/flock.1.html
flock -n rsyncExec.lock -c 'rsync -aAXH --info=progress2 --delete --delete-excluded -e "ssh -p 12345 -i /myuser/.ssh/mykey" /myrepo/mydata/ myuser@mydomain.net:/mybackup/myfolder/'