logg.py

"""
How to use:
cat test.txt | python logg.py
"""
import sys

keywords = ['mmm']

datetime_str = None
# This would be a dictionary
# Keys are dates
# Values are lists of strings which contain one of keywords
result = {}
for line in sys.stdin:
    # Skip blank lines
    if not line.strip() or line.strip().index('#') == 0:
        continue
    # Handle lines with "check_time"...
    elif 'check_time' in line:
        # Assuming format is "check_time<space>:<space>1970/01/01"
        # line.split()[0] would be "check_time"
        # line.split()[1] would be ":"
        # line.split()[2] would be the date we're looking for
        datetime_str = line.split()[2]
        # This would help with '2017-01-01T00:00:00' format
        for c in ['T', '_']:
            if c in datetime_str:
                datetime_str = datetime_str[:datetime_str.index(c)]
    # Handle non-blank lines without "check_time"...
    else:
        for keyword in keywords:
            if keyword in line:
                if datetime_str not in result:
                    result[datetime_str] = [line]
                else:
                    result[datetime_str].append(line)
                break

for datetime_str in result:
    print '%s -- %d' % (datetime_str, len(result[datetime_str]))

test.txt

check_time : 2017/06/21 xxx
mmm
hhh
mmm
check_time : 2017/0622
mmm
mmm
kkk
check_time : 2017/06/23
jjj
lll
mmm
mmm
mmm