#!/bin/sh
# check_procmail - check for errors in procmail "from" file
# Show any lines that don't look like one of these lines:
#
#  From jpeek@jpeek.com  Sun Jan 11 00:02:01 1998
#   Subject: MH PostScript download log
#    Folder:  /usr/bin/gzip >>/u/jpeek/procmail/mail.gz                    8064
#
# Show unique errors that weren't shown last time.
#
# Usage (typically from a cron job):
#    check_procmail address
# where "address" is the email address where changes should be mailed
#
# Installation:
# - At top of script, set the current directory for the tracking files
#   and check that values of variables $logfile and $mailer are okay.
# - In the tracking files directory, create an empty file for $last_errors:
#     touch check_procmail.lasterrs

# This old script is in the public domain.  Do what you want with it.
# Use at your own risk.  I'd appreciate email about bugs and enhancements.
#
#                              Jerry Peek, jpeek@jpeek.com
 
cd $HOME/lib/at_cron || exit 1        # holds tracking files (abort if missing)
 
good_log_lines='^(From | [Ss][Uu][Bb][Jj][Ee][Cc][Tt]: |  Folder: .*[0-9]+)$'

last_errors=check_procmail.lasterrs   # previous log
logfile=$HOME/procmail/from           # procmail's log file
mailer=/usr/bin/mail		      # mail program with -s "subject" option
mailto=${*?}                          # mail to this address (abort if missing)
tempa=/tmp/CK_PMa$$
tempb=/tmp/CK_PMb$$
tempc=/tmp/CK_PMc$$
trap 'rm -f $tempa $tempb $tempc; exit' 0 1 2 15  # removes temp files on exit
umask 77                              # makes temp files readable by owner only
 
# Find all log lines that don't match $good_log_lines:
egrep -v "$good_log_lines" $logfile | sort -u > $tempa

# If any differences, email them and update the $last_errors tracking file:
diff $last_errors $tempa > $tempb || {
    mv $last_errors ${last_errors}.old
    cp $tempa $last_errors

    # diff may output only "<" lines if $logfile was replaced or truncated.
    # So don't show them; only show ">" lines that "diff" showed to be new:
    grep "^>" $tempb > $tempc
    if [ -s $tempc ]
    then $mailer -s "Procmail errors? Check '$logfile' file" $mailto < $tempc
    fi
}