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When using the tar utility to store files in backups one loses the extended ACLs.

Is there some commonly used and not hackish solution (like: create a script that will recrate the ACLs from scratch) to preserve the ACLs?

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7 Answers 7

14

Actually, I believe the question was not about the (standard) file permission bits, but extended ACL information (see setfacl(1) or acl(5)).

To my knowledge, the unmodified GNU tar ignores ACL information. (The man page for GNU tar 1.15.1 as shipped with RHEL 5.2 mentions switches --acls and --no-acls, but I haven't gotten them to work.)

However, the star program is able to back up and restore ACLs, if you select the exustar format:

star -c -p -acl artype=exustar -f archive.tar  files...
star -x -acl -f archive.tar

Star home page: http://cdrecord.berlios.de/new/private/star.html Star is available in ubuntu, at least.

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  • This looks like what I seek, I will have to take a look on that. Now I need to buy some more hours per day ;)
    – silk
    Sep 6, 2010 at 10:29
  • 3
    star is not available on Debian and does not seem to be maintained by a "team". The project is still alive and maintained after 30+ years though. Try bsdtar if you want something else.
    – Totor
    Apr 22, 2013 at 15:35
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    after shutdown of belios you may find it here: sourceforge.net/projects/s-tar/files Apr 25, 2015 at 12:10
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I'm looking for a solution as well so far I found this:

first do a getfactl from my folder

getfacl -R /a_folder > folder.acl

then do a regular tar

tar -czvf folder.tar.gz /a_folder

when I extract it

tar -xvf folder.tar.gz

do a setfacl for the permissions.

setfacl --restore=folder.acl

this works for me.

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  • 1
    Thanks. Nothing worked for me on this page[i really mean it, i even compiled star from source, but it failed to do the job]. But this indeed did work. Though not elegant, but works perfect.
    – ashishsony
    Nov 2, 2019 at 21:05
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Using tar

To create:

tar --acls -cpf backup.tar some-dir-or-file

To untar:

tar --acls -xpf backup.tar
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  • 3
    tar: unrecognized option '--acls' does not work.
    – maniat1k13
    Feb 20, 2013 at 12:04
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    Fedora has non-standard GNU Tar patches that include --acls
    – user55149
    Dec 22, 2013 at 10:53
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    In Debian, tar doesn't support --acls until jessie. (See bug #732071.) The feature is also available in the package from wheezy-backports. Jun 27, 2014 at 5:06
  • Note that said wheezy-backports version of tar has a bug wrt the --acls option. Tarball extraction using said option will assign acl's, even if the archive had none(!). See here.
    – Digger
    Jul 31, 2018 at 4:34
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rsync with the -A and/or -X options.
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I suggest you to use bsdtar.

bsdtar backups extended ACL by default, it uses the same syntax as GNU tar, and the archives it produces are readable by GNU tar.

The package and command name (under Debian based distributions) is bsdtar.

bsdtar cf archive.tar /my/folder/using/extd_acl 
bsdtar xf archive.tar 

The 2nd (extract) command restores ACLs.

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  • I can't get it to work, even though I'm sure it worked some time ago. Filed a bug, code.google.com/p/libarchive/issues/detail?id=329 . Jul 27, 2013 at 18:30
  • Same here actually... I tried it on Debian 8 Jessie and it didn't work. :(
    – Totor
    Jun 1, 2018 at 11:37
  • I am using it on Debian (x64, PC) since several years without any problem (wheezy, jessie, and currently stretch on several machines).
    – Binarus
    May 3, 2019 at 13:48
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If you're looking for a simple-to-use yet powerful solution, I'd recommend rdiff-backup.

Basically, it makes a copy of a source directory to a destination directory but it also saves additional information so you can go back in time to whenever you want.

And, of course, it preserves symlinks, special files, hardlinks, permissions, uid/gid ownership and modification times.

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From the tar Man Page.

-p, --same-permissions, --preserve-permissions
             ignore umask when extracting files (the default for root)

It is not actually the act of archiving that alters the access permissions(ACLs), but the act of unpacking them. Tar is very often used to distribute files from one user to another, and so it is thought convenient to apply a users umask when they unpack.

To preserve the files previous permissions, simply ad a p for to your options. For example

Straight tar:

tar xvp some-file

bz.tar:

tar xvjp some-file

gz.tar:

tar xvzp some-file
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  • this does not work.
    – maniat1k13
    Feb 20, 2013 at 11:58
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    Furthermore tar automatically figures out what to extract. There is no need to pass 'j' or 'z'. Dec 11, 2013 at 14:46

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