PHP - Returning the last line in a file?

Question

I'm guessing it's fgets, but I can't find the specific syntax. I'm trying to read out (in a string I'm thinking is easier) the last line added to a log file.

Solution 1

The simplest naive solution is simply:

$file = "/path/to/file";
$data = file($file);
$line = $data[count($data)-1];

Though, this WILL load the whole file into memory. Possibly a problem (or not). A better solution is this:

$file = escapeshellarg($file); // for the security concious (should be everyone!)
$line = `tail -n 1 $file`;

Solution 2

This looks like it is what you are looking for:

tekkie.flashbit.net: Tail functionality in PHP

It implements a function that uses fseek() with a negative index to roll up the file from the end. You can define how many lines you want to be returned.

The code also is available as a Gist on GitHub:

// full path to text file
define("TEXT_FILE", "/home/www/default-error.log");
// number of lines to read from the end of file
define("LINES_COUNT", 10);


function read_file($file, $lines) {
    //global $fsize;
    $handle = fopen($file, "r");
    $linecounter = $lines;
    $pos = -2;
    $beginning = false;
    $text = array();
    while ($linecounter > 0) {
        $t = " ";
        while ($t != "\n") {
            if(fseek($handle, $pos, SEEK_END) == -1) {
                $beginning = true; 
                break; 
            }
            $t = fgetc($handle);
            $pos --;
        }
        $linecounter --;
        if ($beginning) {
            rewind($handle);
        }
        $text[$lines-$linecounter-1] = fgets($handle);
        if ($beginning) break;
    }
    fclose ($handle);
    return array_reverse($text);
}

$fsize = round(filesize(TEXT_FILE)/1024/1024,2);

echo "<strong>".TEXT_FILE."</strong>\n\n";
echo "File size is {$fsize} megabytes\n\n";
echo "Last ".LINES_COUNT." lines of the file:\n\n";

$lines = read_file(TEXT_FILE, LINES_COUNT);
foreach ($lines as $line) {
    echo $line;
}

Solution 3

define('YOUR_EOL', "\n");
$fp = fopen('yourfile.txt', 'r');

$pos = -1; $line = ''; $c = '';
do {
    $line = $c . $line;
    fseek($fp, $pos--, SEEK_END);
    $c = fgetc($fp);
} while ($c != YOUR_EOL);

echo $line;

fclose($fp);

This is better, since it does not load the complete file into memory...

Set YOUR_EOL to your correct line endings, if you use the same line endings as the default line endings of the OS where your script resides, you could use the constant PHP_EOL.

Solution 4

function seekLastLine($f) {
    $pos = -2;
    do {
        fseek($f, $pos--, SEEK_END);
        $ch = fgetc($f);
    } while ($ch != "\n");
}

-2 because last char can be \n

Solution 5

You either have to read the file in line by line and save the last read line to get it.

Or if on unix/linux you might consider using the shell command tail

tail -n 1 filename

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