linux – “chattr a”对目录的影响是什么？

Linux文件属性通常记录为适用于文件.

chattr(1)联机帮助页：

A file with the ‘a’ attribute set can only be open in append mode for writing.

ext4 wiki：

0x20 File can only be appended (07001).

我的问题是：

> chattr仅限于文件吗？
>它是否在新的子目录和文件上递归？

解决方法:

仅附加标志(chattr a)阻止删除目录,以及直接在该目录中创建的文件和目录：

创建测试目录和文件：

# mkdir     /tmp/foo
# chattr +a /tmp/foo

该目录无法删除：

# rmdir     /tmp/foo
rmdir: failed to remove ‘/tmp/foo’: Operation not permitted

现在在其中创建文件和目录：

# touch     /tmp/foo/bar
# mkdir     /tmp/foo/baz

让我们检查：

# lsattr -d /tmp/foo /tmp/foo/ba*
-----a-------e-- /tmp/foo
-------------e-- /tmp/foo/bar
-------------e-- /tmp/foo/baz

试着抹去东西：

# rm     /tmp/foo/bar
rm: cannot remove ‘/tmp/foo/bar’: Operation not permitted
# rmdir  /tmp/foo/baz
rmdir: failed to remove ‘/tmp/foo/baz’: Operation not permitted
rm -Rf /tmp/foo
rm: cannot remove ‘/tmp/foo/bar’: Operation not permitted
rm: cannot remove ‘/tmp/foo/baz’: Operation not permitted

最后,子目录和子目录中的文件不受保护：

# mkdir            /tmp/foo/baz/bat
# touch            /tmp/foo/baz/baff
# rm --verbose -Rf /tmp/foo/baz
removed directory: ‘/tmp/foo/baz/bat’
removed ‘/tmp/foo/baz/baff’
rm: cannot remove ‘/tmp/foo/baz’: Operation not permitted

再次注意,只有/ tmp / foo有append标志：

# lsattr -d  /tmp/foo /tmp/foo/baz
-----a-------e-- /tmp/foo
-------------e-- /tmp/foo/baz

标签：linux,directory,xattr
来源： https://codeday.me/bug/20190812/1644457.html