Is there a way to for the tar command to check for new files that are not already in the archive, or those that have been deleted (for good measure)?
You could use
tar -d to see if local filesystem files are different or missing.
To add new files, just use
tar -u to add only files newer than the copy in the archive.
tar -cvf /tmp/backup.tar /home # adds all files echo Hello > /home/newfile.txt tar -uvf /tmp/backup.tar /home # adds only newfile.txt rm /home/newfile.txt tar -df /tmp/backup.tar /home # gives an error about newfile.txt missing