I think you misunderstood the [, $level] part of the docs: it's intended to mean that the ", 1" part is optional. As you wrote it it simply won't compile. 

syntax error at test.pl line 3, near "[,"
Execution of test.pl aborted due to compilation errors.

[download]
Try this: 
   use Compress::Zlib;
   my $str_to_compress='a big string';
   $compressed_str=compress($str_to_compress,1);
   $decompressed_str=uncompress($compressed_str);
   print $decompressed_str;

[download]

By the way, please note exact error message text next time. Paraphrasing errors will only confuse people.

"What should it profit a man, if he should win a flame war, yet lose his cool?"

In reply to Re: decompressing the string by Joost
in thread decompressing the string by mohan123

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