PERL Miscellaneous - trouble with Archive::Tar : Can not read compressed format in tar-mode

Author

trouble with Archive::Tar : Can not read compressed format in tar-mode

benoit Guyon

2005-07-26, 4:06 am

hello,

i have a problem when reading a tar.Z file :

the code is :

# ----------------------------------------------------
#!/usr/local/bin/perl -w

use strict;
use warnings;
use Archive::Tar;

my $arch_name_tar_Z = 'myfile.tar.Z';

my $tar = Archive::Tar->new;
$tar->read($arch_name_tar_Z, 1)
or die("*** ERROR read Archive::Tar: $!");
# ----------------------------------------------------

and the error is :
Can not read compressed format in tar-mode

i tried the commands :
tar -xzvf myfile.tar.Z -> OK (i get valid files)
uncompress myfile.tar.Z -> OK (i get a valid myfile.tar file)
gunzip myfile.tar.Z -> OK (i get a valid myfile.tar file)

i checked the code in Tar.pm, and found

unless( $read++ ) {
my $gzip = GZIP_MAGIC_NUM;
if( $chunk =~ /$gzip/ ) {
$self->_error( qq[Can not read compressed format in tar-mode] );
return;
}
}

is my archive compressed with an exotic compressor ? why can the batch
tar command successfully do the job ?

does somebody have an idea to help me ?

best regards

benoit

PS : i tried to build a IO::Zlib Handle on the file (success) and then
to pass it to the Archive::Tar->read function, but i get the same error
message.

PS 2 : Archive::Tar->can_handle_compressed_files gives true

Paul Marquess

2005-07-26, 9:02 am

Archive::Tar can optionally make use of IO::Zlib to access compressed tar
files that have been compressed with gzip. The problem is your tar file has
been compressed with something different, namely the Unix compress program.

Try opening Archive::Tar like this

my $arch_name_tar_Z = 'myfile.tar.Z';
open F, "uncompress -c $arch_name_tar_Z |";
my $tar = Archive::Tar->new(*F);

Paul

"benoit Guyon" <REMOVEMEbguyon1@gfi.frREMOVEME> wrote in message
news:dc4tta$u5k$1@news1.completel.net...
> hello,
>
> i have a problem when reading a tar.Z file :
>
> the code is :
>
> # ----------------------------------------------------
> #!/usr/local/bin/perl -w
>
> use strict;
> use warnings;
> use Archive::Tar;
>
> my $arch_name_tar_Z = 'myfile.tar.Z';
>
> my $tar = Archive::Tar->new;
> $tar->read($arch_name_tar_Z, 1)
> or die("*** ERROR read Archive::Tar: $!");
> # ----------------------------------------------------
>
> and the error is :
> Can not read compressed format in tar-mode
>
> i tried the commands :
> tar -xzvf myfile.tar.Z -> OK (i get valid files)
> uncompress myfile.tar.Z -> OK (i get a valid myfile.tar file)
> gunzip myfile.tar.Z -> OK (i get a valid myfile.tar file)
>
> i checked the code in Tar.pm, and found
>
> unless( $read++ ) {
> my $gzip = GZIP_MAGIC_NUM;
> if( $chunk =~ /$gzip/ ) {
> $self->_error( qq[Can not read compressed format in tar-mode] );
> return;
> }
> }
>
> is my archive compressed with an exotic compressor ? why can the batch
> tar command successfully do the job ?
>
> does somebody have an idea to help me ?
>
> best regards
>
> benoit
>
> PS : i tried to build a IO::Zlib Handle on the file (success) and then
> to pass it to the Archive::Tar->read function, but i get the same error
> message.
>
> PS 2 : Archive::Tar->can_handle_compressed_files gives true

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