linux cli table rapresentation of the last logins (last command)

• chmod 764 setup.sh
• ./setup.sh

Parental Advisory: Explicit Tuples this code has been quickly pached toghether to just w0rk, any attempt to make sense of obscure nested structures is discouraged unless in the presence of an adult. A polished version is been developed by the minute by our team of trained pizzaboys

get output from last command --> $ last | python lastToLog.py

• from raw entries..

reboot   system boot  4.10.0-35-generi Wed Oct  4 05:24 - 13:36  (08:12)
user     tty7         :0               Tue Oct  3 17:58 - 05:24  (11:25)

• ..extract time intervals and save them to logfile. (original idea is to collect them at system startup. building a log of time spent on the host) as:

Wed Oct 4 05:24 -> 13:36 (08:12)
Tue Oct 3 17:58 -> 05:24 (11:25)

Build a horrifying data structure to represent the calendar in the form of:

cal = [ day1, day2 .. dayn ]
where: day = ( daynumber, [ hour1, hour2 .. hour24 ] ]
  and: hour = [ 1half, 2half ]

fill the 1half. 2half chars accoding to intervals read from log tadaaa

instead of this piping bash logging nonsense, can we read entries directly from source on disk? well yes of course, last reads from /var/log/wtmp and we can do the same. utmp file structure is not straightforward, values unpacking is necessary (thx Kexian Li)

we now have wtmp entries:

['6', '1740', 'tty1', 'tty1', 'LOGIN', '', '0', '0', '1740', '1506949239', '359116', '0', '0', '0', '0']
['5', '1740', 'tty1', 'tty1', '', '', '0', '0', '1740', '1506949239', '359116', '0', '0', '0', '0']
['1', '53', '~', '~~', 'runlevel', '4.10.0-35-generic', '0', '0', '0', '1506949239', '348493', '0', '0', '0', '0']
['2', '0', '~', '~~', 'reboot', '4.10.0-35-generic', '0', '0', '0', '1506949222', '76766', '0', '0', '0', '0']

dat we interpret as:

2017/10/02 13:00:39 (359116) [login] - LOGIN - 
2017/10/02 13:00:39 (359116) [ init] - 1740 - tty1
2017/10/02 13:00:39 (348493) [runlv] - runlevel - 4.10.0-35-generic
2017/10/02 13:00:22 ( 76766) [ boot] - reboot - 4.10.0-35-generic

How do we correlate this data in a smart way?