fgets

A better example, to illustrate the differences in speed for large files, between fgets and stream_get_line.This example simulates situations where you are reading potentially very long lines, of an uncertain length (but with a maximum buffer size), from an input source.As Dade pointed out, the previous example I provided was much to easy to pick apart, and did not adequately highlight the issue I was trying to address.Note that specifying a definitive end-character for fgets (ie: newline), generally decreases the speed difference reasonably significantly. #!/usr/bin/php<?php        $plaintext=file_get_contents('http://loripsum.net/api/60/verylong/plaintext');  # Should be around 90k characters        $plaintext=str_replace("\n"," ",$plaintext); # Get rid of newlines        $fp=fopen("/tmp/SourceFile.txt","w");        for($i=0;$i<100000;$i++) {                fputs($fp,substr($plaintext,0,rand(4096,65534)) . "\n");        }        fclose($fp);        $fp=fopen("/tmp/SourceFile.txt","r");        $start=microtime(true);        while($line=fgets($fp,65535)) {                1;        }        $end=microtime(true);        fclose($fp);        $delta1=($end - $start);        $fp=fopen("/tmp/SourceFile.txt","r");        $start=microtime(true);        while($line=stream_get_line($fp,65535)) {                1;        }        $end=microtime(true);        fclose($fp);        $delta2=($end - $start);        $pdiff=$delta1/$delta2;        print "stream_get_line is " . ($pdiff>1?"faster":"slower") . " than fgets - pdiff is $pdiff\n";?>$ ./testcase.php stream_get_line is faster than fgets - pdiff is 1.760398041785Note that, in a vast majority of situations in which php is employed, tiny differences in speed between system calls are of negligible importance.

if you for some reason need to get lines from a string instead of a file pointer, try<?phpfunction string_gets(string $source, int $offset = 0, string $delimiter = "\n"): ?string{    $len = strlen($source);    if ($len < $offset) {        // out of bounds.. maybe i should throw an exception        return null;    }    if ($len === $offset) {        // end of string..        return null;    }    $delimiter_pos = strpos($source, $delimiter, $offset);    if ($delimiter_pos === false) {        // last line.        return substr($source, $offset);    }    return substr($source, $offset, ($delimiter_pos - $offset) + strlen($delimiter));}?>(i had a ~16GB string in-memory i needed to process line-by-line, but i would get memory-allocation-crash (on a 32GB ram system) if i tried explode("\n",$str); , so came up with this.. interestingly, fgets() seems to be faster than doing it in-ram-in-php, though. php 7.3.7)

There's an error in the documentation:The file pointer must be valid, and must point to a file successfully opened by fopen() or fsockopen() (and not yet closed by fclose()).You should also add "popen" and "pclose" to the documentation. I'm a new PHP developer and went to verify that I could use "fgets" on commands that I used with "popen".

fscanf($file, "%s\n") isn't really a good substitution for fgets(), since it will stop parsing at the first whitespace and not at the end of line!(See the fscanf page for details on this)

I think that the quickest way of read a (long) file with the rows in  reverse order is<?php$myfile = 'myfile.txt';$command = "tac $myfile > /tmp/myfilereversed.txt";passthru($command);$ic = 0;$ic_max = 100;  // stops after this number of rows$handle = fopen("/tmp/myfilereversed.txt", "r");while (!feof($handle) && ++$ic<=$ic_max) {   $buffer = fgets($handle, 4096);   echo $buffer."<br>";}fclose($handle);?>It echos the rows while it is reading the file so it is good for long files like logs.Borgonovo