tail -f a.txt | grep 'python'

# tail -f a.txt |grep 'python'

#tail -f a.txt
import time
def tail(conf):
    with open(conf,encoding='utf-8') as f:
        f.seek(0,2)
        while True:
            f1 = f.readline().strip()
            if f1:
                yield f1
            else:
                time.sleep(0.5)

# t = tail('a.txt')
# print(next(t))
# for line in t:
#     print(line)

#  grep 'python'
def grep(kewords,lines):
    for line in lines:
        if kewords in line:
            yield line
g = grep('python',tail('a.txt'))
for i in g:
    print(i)