How to create a tar file that omits timestamps for its contents?

Question

Is there a way to create a .tar file that omits the values of atime/ctime/mtime for its files/directories?

Why do we want to do this?

We have a st

Answer 1

GNU tar has a --mtime argument, which can be used to store a fixed date in the archive rather than a file's actual mtime:

tar --mtime='1970-01-01' input ...

When compressing a tarball with gzip, it's also necessary to specify -n to prevent name and timestamp of the tar archive from being stored:

tar --mtime='1970-01-01' input ... | gzip -n >input.tar.gz

Answer 2

To have a truly idempotent tar, mtime is a good step but not enough. You also need to set the sort order, the owner and group (together with their mapping) and a proper timezone for mtime (since otherwise you're gonna have issues as well between Mac and Linux).

I ended up with

tar --sort=name --owner=root:0 --group=root:0 --mtime='UTC 2019-01-01' ... | gzip -n

Answer 3

We can create the tar file without timestamp appending to it.

1) Create tar file without compression and timestamp

tar -cf file_name.tar file_name

2) Create tar file with compression and without timestamp

tar -cf file_name | gzip -n > file_name.tar.gz

3) Alternate way

GZIP=-n tar -czf file_name.tar.gz file_name

Note: '-n' will not add timestamp and name

4) To extract tar file

tar -xf file_name.tar and tar -xzf file_name.tar.gz

To verify you can do like this

file file_name.tar or file_name.tar.gz
output = file_name.tar.gz: gzip compressed data, from Unix