Sync 1 config file amongst multiple directories

Lets say I have 4 java instances running on my linux system, in separate directories, all of which have a config file named config.yml. I want to be able to edit 1 config.yml and have it copy across the multiple directories in real time. For example: - ../dir1/config.yml - ../dir2/config.yml - ../dir3/config.yml - ../dir4/config.yml I want dir2 and dir3 to reference the config.yml in dir1. Is there a linux-based program or software that will allow me to do this? Or allow me to quickly sync the config.yml file across the directories? In addition to this question, would it be possible to have it sync across multiple systems, too? Thanks in advance!