Small shell script to regularly check a target person's responsiveness via mail.

When run as "pingmail check", tries to derive the last time a person sent a
mail to the local system by either a) searching a maildir for the most recent
file matching a regex pattern (such as a "From: " field matching the target
person), and looking at thta file's modification time, or b) checking the
modification time of a defined mailbox file. If that point in time is too
distant, sends an e-mail to the target person requesting some sign of life.
After some more wait time without a sign of life, sends a warning message to
another mail address that target person is unresponsive.

When run as "pingmail check", searches a maildir for the most recent file
matching a regex pattern (such as a "From: " field matching the target person),
and if the most recent file is too old, sends an e-mail to the target person
requesting some sign of life. After some more wait time without a sign of life,
sends a warning message to another mail address that target person is
unresponsive.

The wait time counter can be reset manually with "pingmail touch".

The wait time, the target and checking persons' mail addresses, the regex, the
maildir path etc. must be set in a dotfile ~/.pingmailrc. See comments in
pingmailrc.example file for more details.

To install as an hourly cronjob, define $path_to_pingmail_script_file, then do:

line='0 * * * * '$path_to_pingmail_script_file' check > /dev/null'
(crontab -l; echo "$line") | crontab -