On 6/3/22 03:13, Piotr P. Stefaniak wrote:
2. How about a simpler option which basically says: warn only about
changes to any of the following: st_mtime, st_uid, st_gid, st_mode,
st_size. It's not clear that the extra complexity of a more-complicated
option is worth the aggravation.
This wouldn't be perfect for my use case; I want my shell script to
abort execution (set -e -o pipefail) iff tar observes a content change
in the file that is expected to never change.
Sorry, I'm not quite understanding.
First, if I understand things correctly, the patch you sent won't cause
'tar' to abort execution, only to issue a warning. Or are you saying
you'll send tar's stderr to a pipe with no reader, so that the warning
will cause 'tar' to exit? If so, that sounds less reliable than it could be.
Second, I know you're not suggesting the only perfectly-reliable way to
know the content hasn't changed, which is to save a copy and compare the
content to the saved copy. Instead, you're suggesting a heuristic A that
involves looking only at the mtime and size. That differs the heuristic
B that I suggested, in that B generates a warning if the file's uid,
gid, or mode changes, whereas A does not. In your use case, why is it
harmful for B to generate those extra warnings?
