All commands tested on Mac OS Monterey / Sep 12, 2023

How to update a tar archive with new or changed files

Update an existing tar archive with new or changed files.

You can use this short tar command.

              
                  tar -uvf files.tar files/my-file.txt

Or this more verbose tar command.

              
                  tar --update --verbose --file files.tar files/my-file.txt

Note: The above will only work on uncompressed tar archives. Ie. files.tar.

To update a file in a compresed archive Ie files.tar.gz, you'll need to extract the .tar.gz file to a .tar before you update the file.

Options explained

u or --update tells tar to add to the archive if the modification time is newer than in the archive
v or --verbosetells tar to produce verbose output
f or --filetells tar that the next parameter will be the tar file to create, extract, append to, list, etc.