sync two dir on local or remote

sync-dir.sh

 To sync the contents of dir1 to dir2 on the same system, type:

rsync -av --progress --delete dir1/ dir2
-a, --archive
        archive mode

--delete
        delete extraneous files from dest dirs

-v, --verbose
        Verbose mode (increase verbosity)

--progress
        show progress during transfer

                        — from rsync(1)

Note : The / after dir1 is necessary to mean "the contents of dir1".  Without the trailing slash, would place dir1, including the directory, within dir2. This would create a hierarchy that looks like:

…/dir2/dir1/[files]