bsdtar：如何避免覆蓋現有文件資訊？

bsdtar有一個-k (Do not overwrite existing files)選項，可以避免更改任何現有文件的內容，但它仍然會用存檔中的內容覆蓋文件資訊（例如權限）。有沒有辦法bsdtar完全跳過覆蓋現有文件，使文件資訊保持不變，就像該--skip-old-files選項在 GNU tar 中的工作方式一樣？

這是一個展示問題的腳本：

#!/usr/bin/env bash

echo -e "\nCreate an archive with normal files"
rm -rf test-tar
mkdir test-tar
echo "TEST CONTENTS 1" > test-tar/1.txt
echo "TEST CONTENTS 2" > test-tar/2.txt
ls -la test-tar
bsdtar -czf test.tgz test-tar

echo -e "\nChange contents and permissions of one of the files"
echo "MORE CONTENTS" >> test-tar/2.txt
chmod 000 test-tar/2.txt
ls -la test-tar

echo -e "\nUntar the archive with -k (Do not overwrite existing files). The file contents are intact, but the file permissions have changed"
bsdtar -xzkf test.tgz
ls -la test-tar
cat test-tar/2.txt

echo -e "\nUntar the archive without -k"
bsdtar -xzf test.tgz
ls -la test-tar
cat test-tar/2.txt

這是腳本輸出：

Create an archive with normal files
total 16
drwxr-xr-x   4 rbrainard  wheel  136 Nov 29 17:53 .
drwxr-xr-x  14 rbrainard  wheel  476 Nov 29 17:53 ..
-rw-r--r--   1 rbrainard  wheel   16 Nov 29 17:53 1.txt
-rw-r--r--   1 rbrainard  wheel   16 Nov 29 17:53 2.txt

Change contents and permissions of one of the files
total 16
drwxr-xr-x   4 rbrainard  wheel  136 Nov 29 17:53 .
drwxr-xr-x  14 rbrainard  wheel  476 Nov 29 17:53 ..
-rw-r--r--   1 rbrainard  wheel   16 Nov 29 17:53 1.txt
----------   1 rbrainard  wheel   30 Nov 29 17:53 2.txt

Untar the archive with -k (Do not overwrite existing files). The file contents are intact, but the file permissions have changed
total 16
drwxr-xr-x   4 rbrainard  wheel  136 Nov 29 17:53 .
drwxr-xr-x  14 rbrainard  wheel  476 Nov 29 17:53 ..
-rw-r--r--   1 rbrainard  wheel   16 Nov 29 17:53 1.txt
-rw-r--r--   1 rbrainard  wheel   30 Nov 29 17:53 2.txt
TEST CONTENTS 2
MORE CONTENTS

Untar the archive without -k
total 16
drwxr-xr-x   4 rbrainard  wheel  136 Nov 29 17:53 .
drwxr-xr-x  14 rbrainard  wheel  476 Nov 29 17:53 ..
-rw-r--r--   1 rbrainard  wheel   16 Nov 29 17:53 1.txt
-rw-r--r--   1 rbrainard  wheel   16 Nov 29 17:53 2.txt
TEST CONTENTS 2

我的bsdtar版本是3.3.2.

原來這是一個錯誤。我將它交叉發佈到 libarchive-discuss並且其中一位維護者做出了這樣的回應。在以下位置提出問題：https ://github.com/libarchive/libarchive/issues/972

引用自：https://unix.stackexchange.com/questions/407696