用PHP替换大文件中的字符串

Question

我试图在PHP中为整个文件执行字符串替换.我的文件超过100MB所以我必须逐行,不能使用file_get_contents().有一个很好的解决方案吗？

Answer 1

如果您不需要使用PHP,我强烈建议您从命令行执行这样的操作.它是最好的工具,更容易使用.

在任何情况下,sed(流编辑器)命令都是您正在寻找的:

sed s/search/replace oldfilename > newfilename

如果您需要不区分大小写:

sed -i s/search/replace oldfilename > newfilename

如果您需要在PHP中动态执行此操作,您可以使用passthru():

$output = passthru("sed s/$search/$replace $oldfilename > $newfilename");

Answer 2

干得好:

function replace_file($path, $string, $replace)
{
    set_time_limit(0);

    if (is_file($path) === true)
    {
        $file = fopen($path, 'r');
        $temp = tempnam('./', 'tmp');

        if (is_resource($file) === true)
        {
            while (feof($file) === false)
            {
                file_put_contents($temp, str_replace($string, $replace, fgets($file)), FILE_APPEND);
            }

            fclose($file);
        }

        unlink($path);
    }

    return rename($temp, $path);
}

像这样称呼它:

replace_file('/path/to/fruits.txt', 'apples', 'oranges');

Answer 3

如果您不能直接从命令行使用 sed，因为它是一个动态任务，并且您需要从 php 调用它，那么很难获得正确的语法：您必须在搜索和替换字符串中以不同的方式转义这些字符

' / $ . * [ ] \ ^ &

以下函数搜索并替换文件中的字符串，而不将搜索到的字符串解释为正则表达式。因此，如果您愿意，可以搜索字符串“.*”并将其替换为“$”。

/**
 * str_replace_with_sed($search, $replace, $file_in, $file_out=null)
 * 
 * Search for the fixed string `$search` inside the file `$file_in`
 * and replace it with `$replace`. The replace occurs in-place unless
 * `$file_out` is defined: in that case the resulting file is written
 * into `$file_out`
 *
 * Return: sed return status (0 means success, any other integer failure)
 */
function str_replace_with_sed($search, $replace, $file_in, $file_out=null)
{
    $cmd_opts = '';
    if (! $file_out) 
    {
        // replace inline in $file_in
        $cmd_opts .= ' -i';
    }

    // We will use Basic Regular Expressions (BRE). This means that in the 
    // search pattern we must escape
    // $.*[\]^
    //
    // The replacement string must have these characters escaped
    // \ & 
    //
    // In both cases we must escape the separator character too ( usually / )
    // 
    // Since we run the command trough the shell we We must escape the string
    // too (yai!). We're delimiting the string with single quotes (') and we'll
    // escape them with '\'' (close string, write a single quote, reopen string)    

    // Replace all the backslashes as first thing. If we do it in the following
    // batch replace we would end up with bogus results
    $search_pattern = str_replace('\\', '\\\\', $search);

    $search_pattern = str_replace(array('$', '.', '*', '[', ']', '^'),
                                  array('\\$', '\\.', '\\*', '\\[', '\\]', '\\^'),
                                  $search_pattern);

    $replace_string = str_replace(array('\\', '&'),
                                  array('\\\\', '\\&'),
                                  $replace);

    $output_suffix = $file_out ? " > '$file_out' " : '';
    $cmd = sprintf("sed ".$cmd_opts." -e 's/%s/%s/g' \"%s\" ".$output_suffix,
                    str_replace('/','\\/', # escape the regexp separator
                      str_replace("'", "'\''", $search_pattern) // sh string escape
                    ),
                    str_replace('/','\\/', # escape the regexp separator
                      str_replace("'", "'\''", $replace_string) // sh string escape
                    ),
                    $file_in
                  );

    passthru($cmd, $status);

    return $status;
}