如何检测换行中的文件结尾？

with open('file.txt', 'r') as file:
    for line in file:
        # 处理每一行
        pass

BufferedReader reader = new BufferedReader(new FileReader("file.txt"));
String line = reader.readLine();
while (line != null) {
    // 处理每一行
    line = reader.readLine();
}
reader.close();

const fs = require('fs');
const readline = require('readline');

const readInterface = readline.createInterface({
    input: fs.createReadStream('file.txt'),
    output: process.stdout,
    console: false
});

readInterface.on('line', function(line) {
    // 处理每一行
});

using (StreamReader reader = new StreamReader("file.txt"))
{
    string line;
    while ((line = reader.ReadLine()) != null)
    {
        // 处理每一行
    }
}

$file = fopen("file.txt", "r");
while (($line = fgets($file)) !== false) {
    // 处理每一行
}
fclose($file);