Answer by aneeshep for Why crontab scripts are not working?

Cron daemon is not running. I really screwed up with this some months ago.

Type:

pgrep cron 

If you see no number (i.e. cron's main PID), then cron is not running. sudo /etc/init.d/cron start can be used to start cron.

EDIT: Rather than invoking init scripts through /etc/init.d, use the serviceutility, e.g.

sudo service cron start

EDIT: Also you could use systemctl in modern Linux, e.g.

sudo systemctl start cron