You are not showing is the exact code you are using when you get to the named error message Can't use an undefined value as an array reference...

The code you show will produce the following message: Global symbol "@apple" requires explicit package name at $0 line 6.

Test with this: perl -e 'use strict; my $buffer = \@apple'

So what is the code you are actually using?

Cheers, Sören

Sorry, I forgot to define the array when I type the code here.

 
    #!/usr/bin/perl
    use Data::Dumper;
    use strict ;
    use warnings ;
    use IO::Uncompress::Bunzip2 qw(bunzip2 $Bunzip2Error) ;
    use IO::File ;
    my $input = new IO::File "<tmp.bz2" or die "Cannot open 'tmp.bz2':
+ $!\n" ;
    my @apple;
    my $buffer = \@apple;
    bunzip2 $input => $buffer or die "bunzip2 failed: $Bunzip2Error\n
+";
    foreach (@{$buffer})
    {
        if (/good(.*)/)
        {
            print $1;
        }
    }
[download]

This is the code I wrote to read a txt contain in tmp.bz2 which contain: goodmorning goodbye goodafternoon and supposed to output: morning bye afternoon but it doesn't work.

... if (/good(.*)/)

This is much better.
Although $buffer now contains:

$VAR1 = \[
            \'goodmorning goodbye goodafternoon
'
          ];
[download]

So although there's your array, it only contains scalar value referenced inside. I think that's not the behaviour you expected from the IO::Uncompress::Bunzip2 documentation talking about arrays.
There it says:

If $output is an array reference, the uncompressed data will be pushed onto the array.

That is, all of the bunzipped data is pushed onto the array, so you can fill your array with data from several bunzipped files.

Change the matching to if ($$_ =~ /good(.*)/) to make your code output the value.

If you also want to break the result into a list, use split to do that.

Cheers, Sören

cheers

baxy

@apple has nothing to be defined, it is used to store the content of the text from bz2. The content in $buffer will be pushed into @apple, as mentioned in the doc page. But I wonder why it just doesn't work.

use Data::Dumper;

    use strict ;
    use warnings ;
    use IO::Uncompress::Bunzip2 qw(bunzip2 $Bunzip2Error) ;
    use IO::File ;
    my $input = new IO::File "<tmp.bz2" or die "Cannot open 'tmp.bz2':
+ $!\n" ;;
    my $buffer;
    bunzip2 $input => \$buffer or die "bunzip2 failed: $Bunzip2Error\n
+";
    print $buffer;
    foreach ($buffer)
    {
        print Dumper($_);;
    }
[download]

This works for me. Why do you need to have an @array defined (by the way i suppose it is defined somewhere else in the code!!). But even then i don't think it is a problem with bzip because if U are getting the output in print $buffer of print @{$buffer} then the problem must be somewhere else in the code. use Data::Dumper to check what is going on at each step in your foreach line.