python 查看文件最新的几行

 

 

import linecache


def get_line_count(filename):
    count = 0
    with open(filename, 'r') as f:
        while True:
            buffer = f.read(1024 * 1)
            if not buffer:
                break
            count += buffer.count('\n')
    return count


def error_log():
    # 读取最后100行
    file = 'log_error.out'
    n = 100
    linecache.clearcache()
    line_count = get_line_count(file)
    print('num: ', line_count)
    line_count_start = line_count - (n - 1)

    if line_count_start < 0:
        n = line_count + 1
        line_count_start = 0

    all_line = []
    for i in range(n):
        last_line = linecache.getline(file, line_count_start)
        # print(line_count_start, last_line)
        all_line.append(last_line)
        line_count_start += 1

    return "".join(all_line)


if __name__ == '__main__':
    print(error_log())