bzopen() opens a bzip2 (.bz2) file for reading or writing.
The name of the file to open.
Similar to the fopen() function ('r' for read, 'w' for write, etc.).
If the open fails, bzopen() returns
it returns a pointer to the newly opened file.
$file = "/tmp/foo.bz2";
$bz = bzopen($file, "r") or die("Couldn't open $file for reading");