How to extract a tarball?

Questions / Help
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1

Background

I have a release file inside a tarball. However I want the final release to have some additional files and to move things around, for the convenience of the user.

This means I need to do 3 things:

  1. Extract the contents of the tarball into a folder
  2. Add the extra files to said folder and move some items around
  3. compress everything again and call it a day

Problem

While I have it clear on how to execute step 2, using File and friends, I have tried several ways to do steps 1 and 3 and I failed.

I have tried using :zip, but it returns a bad encoding error, probably because the file is not a zip but tar instead.

I am also aware of File.open("path", :read, :compressed), but I don’t want to read anything, I want to extract it into a new folder.

I also checked Unzip but it does not fit my use case.

Question

How can I extract a tar file into a folder and compress a folder into a tar file?

2

https://www.erlang.org/doc/man/erl_tar

1 Like
3

Do we have an elixir module/equivalent ?

Using that I have the following error:

> :erl_tar.extract('application-data.tar.gz')
{:error, :invalid_tar_checksum}

So I am guessing I am not passing the correct options, since Windows can extract the file perfectly.

4

I’m guessing it has to be decompressed first.

5

Since are trying to extract gziped tar file .tar.gz, you have to decompress as well.

:erl_tar.extract('something.tar.gz', :compressed)
4 Likes
6

I was able to extract the file using:

:ok = :erl_tar.extract("tar_path", [{:cwd, "tmp"}, :compressed])

This will extract the tar file into the tmp folder. Once there I can do the rest !

1 Like