Autotools - tar This does not look like a tar archive

Question

After running make distcheck I get the message that I have successfully built the package and is ready for distribution. If I untar the tar.gz with tar -zxvf hello-0.2.tar.gz it successfully extracts all of its contents. However, when I try to extract them in different machines I get:

tar: This does not look like a tar archive
tar: Skipping to next header
tar: Exiting with failure status due to previous errors

The weird thing is that it was working before.

On the machine I'm trying to build the package, I've updated my automake 1.10.1, autoconf 2.61, and tar 1.20 to automake 1.11.1, autoconf 2.65, and tar 1.23 and still the same issue.

Any ideas what could be the problem?

Stylography

Does this work: gzip -d hello-0.2.tar.gz followed by: tar -xf hello-0.2.tar – Tantara

@SyggyF: It actually works. Any ideas why this way works and not the other? – Stylography

Answer 1

The problem is not on the build machine; the problem is on the target machines.

Not all versions of tar automatically recognize the decompression to apply to a compressed tar file. Given that gunzip followed by tar does work, then the tar on your target machine is one such. The versions of tar on the mainstream Unix systems (AIX, HP-UX, Solaris) do not recognize compressed tar files automatically. Those on Linux and MacOS X do.

Note that you can use:

gzip -dc hello-0.2.tar.gz | tar -xf -

to avoid creating the intermediate uncompressed file.

Fireguard

1. Is the hyphen in the end just a typo, or does it do something? 2. With this method I get the error tar: Archive is compressed. Use -z option tar: Error is not recoverable: exiting now. If I add -z it gives me tar: -z: Cannot open: No such file or directory. – Lan

(1) The hyphen at the end specifies that the input file is standard input (-f -). (2) You might have a double-compressed file, though it's a bit unlikely. You could try gunzip hello-0.2.tar.gz and then use file hello-0.2.tar to see what file type it thinks you've got. Which version of tar are you using that recognizes that the archive is compressed but does not decompress it? If you use tar -xzf -, you might be OK. If you use tar -xf -z, then you're telling tar that the file to extract from is -z. – Fireguard

Answer 2

Actually this could happen when the server you download from applies another round of GZip and the client you used to download the file doesn't read/respect the HTTP Content-Encoding header and stores the HTTP payload as it was on the wire.

Although the file appears to have only the extension .tar.gz it is in fact .tar.gz.gz. after you run the gunzip once the file gets the extension .tar only but still this time running the tar command tar xf hello-0.2.tar recognizes the GZip format and implicitly runs the file through gunzip one more time before extracting.

You can check this by running head hello-02.tar.gz and head hello-02.tar. GZip is a very binary format, whereas tar is quite human readable. If the .tar file appears "too binary" you have a doubly encoded file on your hands.

Andesine