System information

addition, the -a option (equivalent to -d R --preserve= al l ) of cp also preserves ACLs during a
backup along with other information such as timestamps, SELinux contexts, and the like. For more
information about d ump, tar, or cp, refer to their respective man pages.
The star utility is similar to the tar utility in that it can be used to generate archives of files; however,
some of its options are different. Refer to Table 20.1, “ Command Line Options for star” for a listing of
more commonly used options. For all available options, refer to man star. The star package is
required to use this utility.
T able 20.1. C o mman d Lin e O p t io n s for star
O p t io n Descrip t io n
-c Creates an archive file.
-n Do not extract the files; use in conjunction with -x to show
what extracting the files does.
-r Replaces files in the archive. The files are written to the
end of the archive file, replacing any files with the same
path and file name.
-t Displays the contents of the archive file.
-u Updates the archive file. The files are written to the end of
the archive if they do not exist in the archive, or if the files
are newer than the files of the same name in the archive.
This option only works if the archive is a file or an
unblocked tape that may backspace.
-x Extracts the files from the archive. If used with -U and a file
in the archive is older than the corresponding file on the
file system, the file is not extracted.
-hel p Displays the most important options.
-xhel p Displays the least important options.
-/ Do not strip leading slashes from file names when
extracting the files from an archive. By default, they are
stripped when files are extracted.
-acl When creating or extracting, archives or restores any ACLs
associated with the files and directories.
20.6. Compat ibilit y wit h Older Syst ems
If an ACL has been set on any file on a given file system, that file system has the ext_attr attribute.
This attribute can be seen using the following command:
# tune2fs -l filesystem-device
A file system that has acquired the ext_attr attribute can be mounted with older kernels, but those
kernels do not enforce any ACLs which have been set.
Versions of the e2fsck utility included in version 1.22 and higher of the e2fspro g s package
(including the versions in Red Hat Enterprise Linux 2.1 and 4) can check a file system with the
ext_attr attribute. Older versions refuse to check it.
20.7. ACL References
Refer to the following man pages for more information.
⁠Chapt er 2 0 . Access Cont rol List s
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