Read and parse contents of very large file

Question

I am trying to parse a tab delimited file that is ~1GB in size.

Where I run the script i get:

Fatal error: Allowed memory size of 1895825408 bytes exhausted  (tried to allocate 1029206974 bytes) ...

My script at the moment is just:

$file = file_get_contents('allCountries.txt') ;

$file = str_replace(array("\r\n", "\t"), array("[NEW*LINE]", "[tAbul*Ator]"), $file) ;

I have set the memory limit in php.ini to -1, which then gives me:

Fatal error: Out of memory (allocated 1029963776) (tried to allocate 1029206974 bytes)

Is there anyway to partially open the file and then move on to the next part so less memory is used up at one time?

Answer 1

Yes, you can read it line by line:

$handle = @fopen("/tmp/inputfile.txt", "r");
if ($handle) {
    while (($buffer = fgets($handle, 4096)) !== false) {
        echo $buffer;
    }
    fclose($handle);
}