Swap two files/folders.

swap.php

#!/usr/bin/env php
<?php

function ask($string) {
    echo "$string (y/n): ";

    $handle = fopen("php://stdin","r");
    $line = trim(fgets($handle));

    if ($line == 'y' or $line == 'yes') {
        return true;
    } else {
        return false;
    }
}

function say($key, $string = null) {
    if ( ! $string) {
        $string = $key;
    } else {
        $string = "$key: $string";
    }

    echo "$string\n";
}

////////////////////////////////////////////////////////////////////////////////

function main($args) {
    if (@$args[1] == "update") {
        $file = $args[0];
        $fileBackup = $file . ".bak";

        $script = file_get_contents("https://gist.githubusercontent.com/maximkott/9a79ca2bc40e907d401e/raw");
        $oldScript = file_get_contents($file);

        if ($script == $oldScript) {
            say("error", "gist did not change yet.");
            exit;
        }

        say("starting update...");

        if (file_exists($fileBackup)) {
            unlink($fileBackup);
        }

        rename($file, $fileBackup);
        file_put_contents($file, $script);
        exec("chmod +x $file");

        say("update completed.");

        unlink($fileBackup);

        exit;
    }

    $file1 = @$args[1];
    $file2 = @$args[2];

    if ( ! $file1) {
        say("error", "target and destination paths required.");
        exit;
    } else if ( ! $file2) {
        if (substr($file1, -1) != '/') $file1 = $file1 . "/";

        $file2 = $file1 . "green";
        $file1 = $file1 ."red";
    }

    if ( ! file_exists($file1)) {
        say("error", "bad argument: $file1.");
        exit;
    } else if ( ! file_exists($file2)) {
        say("error", "bad argument: $file2.");
        exit;
    }


    if (ask("swap files $file1 -> $file2?")) {
        $fileTmp = $file1 . "_tmp_" . time();

        rename($file1, $fileTmp);
        rename($file2, $file1);
        rename($fileTmp, $file2);

        say("all done!");
    }
}

main($argv);