I think what you want is maybe the option -u after you make the file name change so that it only updates the files in the archive that have changed?
NAME
tar - The GNU version of the tar archiving utility
SYNOPSIS
tar [ - ] A --catenate --concatenate | c --create | d --diff --compare | r --append | t --list | u --update | x -extract --get [ --atime-preserve ] [ -b, --block-size N ] [ -B, --read-full-blocks ] [ -C, --directory DIR ] [ --checkpoint ]
[ -f, --file [HOSTNAME:]F ] [ --force-local ]
[ -F, --info-script F --new-volume-script F ] [ -G, --incremental ] [ -g, --listed-incremental F ] [ -h, --dereference ] [ -i, --ignore-zeros ] [ -j, -I, --bzip ] [ --ignore-failed-read ] [ -k, --keep-old-files ] [ -K, --starting-file F ] [ -l, --one-file-system ] [ -L, --tape-length N ] [ -m, --modification-time ] [ -M, --multi-volume ] [ -N, --after-date DATE, --newer DATE ] [ -o, --old-archive, --portability ] [ -O, --to-stdout ] [ -p, --same-permissions, --preserve-permissions ] [ -P, --absolute-paths ] [ --preserve ]
[ -R, --record-number ] [ --remove-files ] [ -s, --same-order, --preserve-order ] [ --same-owner ] [ -S, --sparse ] [ -T, --files-from=F ] [ --null ]
[ --totals ]
[ -v, --verbose ] [ -V, --label NAME ] [ --version ]
[ -w, --interactive, --confirmation ] [ -W, --verify ]
[ --exclude FILE ] [ -X, --exclude-from FILE ] [ -Z, --compress, --uncompress ] [ -z, --gzip, --ungzip ]
[ --use-compress-program PROG ] [ --block-compress ] [ -[0-7][lmh] ]
filename1 [ filename2, ... filenameN ]
directory1 [ directory2, ...directoryN ]
DESCRIPTION
This manual page documents the GNU version of tar , an archiving program designed to store and extract files from an archive file known as a tarfile. A tarfile may be made on a tape drive, however, it is also common to write a tarfile to a normal file. The first argument to tar must be one of the options: Acdrtux, followed by any optional functions. The final arguments to tar are the names of the files or directories which should be archived. The use of a directory name always implies that the subdirectories below should be included in the archive.
FUNCTION LETTERS
One of the following options must be used:
-A, --catenate, --concatenate
append tar files to an archive
-c, --create
create a new archive
-d, --diff, --compare
find differences between archive and file system
--delete
delete from the archive (not for use on mag tapes!)
-r, --append
append files to the end of an archive
-t, --list
list the contents of an archive
-u, --update
only append files that are newer than copy in archive
-x, --extract, --get
extract files from an archive
OTHER OPTIONS
--atime-preserve
don't change access times on dumped files
-b, --block-size N
block size of Nx512 bytes (default N=20)
-B, --read-full-blocks
reblock as we read (for reading 4.2BSD pipes)
-C, --directory DIR
change to directory DIR
--checkpoint
print directory names while reading the archive
-f, --file [HOSTNAME:]F
use archive file or device F (default /dev/rmt0)
--force-local
archive file is local even if has a colon
-F, --info-script F --new-volume-script F
run script at end of each tape (implies -M)
-G, --incremental
create/list/extract old GNU-format incremental backup
-g, --listed-incremental F
create/list/extract new GNU-format incremental backup
-h, --dereference
don't dump symlinks; dump the files they point to
-i, --ignore-zeros
ignore blocks of zeros in archive (normally mean EOF)
-j, -I, --bzip
filter the archive through bzip2. Note: -I is deprecated and may get a different meaning in the near future.
--ignore-failed-read
don't exit with non-zero status on unreadable files
-k, --keep-old-files
keep existing files; don't overwrite them from archive
-K, --starting-file F
begin at file F in the archive
-l, --one-file-system
stay in local file system when creating an archive
-L, --tape-length N
change tapes after writing N*1024 bytes
-m, --modification-time
don't extract file modified time
-M, --multi-volume
create/list/extract multi-volume archive
-N, --after-date DATE, --newer DATE
only store files newer than DATE
-o, --old-archive, --portability
write a V7 format archive, rather than ANSI format
-O, --to-stdout
extract files to standard output
-p, --same-permissions, --preserve-permissions
extract all protection information
-P, --absolute-paths
don't strip leading `/'s from file names
--preserve
like -p -s
-R, --record-number
show record number within archive with each message
--remove-files
remove files after adding them to the archive
-s, --same-order, --preserve-order
list of names to extract is sorted to match archive
--same-owner
create extracted files with the same ownership
-S, --sparse
handle sparse files efficiently
-T, --files-from=F
get names to extract or create from file F
--null
-T reads null-terminated names, disable -C
--totals
print total bytes written with --create
-v, --verbose
verbosely list files processed
-V, --label NAME
create archive with volume name NAME
--version
print tar program version number
-w, --interactive, --confirmation
ask for confirmation for every action
-W, --verify
attempt to verify the archive after writing it
--exclude FILE
exclude file FILE
-X, --exclude-from FILE
exclude files listed in FILE
-Z, --compress, --uncompress
filter the archive through compress
-z, --gzip, --ungzip
filter the archive through gzip
--use-compress-program PROG
filter the archive through PROG (which must accept -d)
