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I am attempting to extract a tarball (*.tgz, to be exact) and receiving terminal errors on extracted symlinks. Unfortunately, I cannot simply recreate the archive as this is a legacy archive for a system that no longer exists which was created before I was even out of high school (have to love working for a big company).

I have consulted the almighty Google; however all I can seem to find is information for excluding / following symlinks at creation time. The exact error I am receiving is something of a misnomer (error: read-only filesystem) and comes from the fact that a very large portion of the data payload is contained within numerous squash / cram / loop filesystems. The symlinks are referencing data within them which, obviously, cannot be mounted due to errors while extracting said tarball. Chicken; meet egg.

So, in short:

How can I extract a *.tgz archive to completion while either ignoring symlinks or ignoring resultant symlink errors?

For reference:

$ tar --version
tar (GNU tar) 1.26
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by John Gilmore and Jay Fenlason.
$ uname -a
Linux localhost.localdomain 3.7.9-205.fc18.x86_64 #1 SMP Sun Feb 24 20:10:02 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
Rui F Ribeiro
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MysteryMoose
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2 Answers2

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-h (or --dereference) to dereference will only work upon creation.

Reference: http://www.gnu.org/software/tar/manual/tar.html#SEC138

According to a similar answer here: How do I dereference links when extracting from a tar file? you can mount the archive then copy from it, though I have not tested this myself.

Community
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JP Doherty
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  • Handy little tidbit to know, thanks! For those who may come looking later: AVFS does work, however it is not immediately available for Fedora 18 x64. It can, however be download without issue and locally installed via yum (use yum; it will grab the FUSE dependency for you). Once I was 'in' the *.tgz archive, the copy went off without a hitch. – MysteryMoose May 20 '13 at 22:21
  • Just putting in a thought from the linked question, the avfs mounting method does not cover use cases where this needs to be done inside of a containerized build system. Fuse is not available and would require a privileged container. So a method to do this without fuse is needed. – Routhinator Mar 30 '23 at 18:38
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What you like can easily be done. Call:

star -x f=archive.tgz -find ! -type l

Recent star sources are in the schilytools package. star is the oldest free tar implementation.

schily
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