#!/bin/sh
mailcontents=mailbody
while read line
do
    if [ ! -f $line ]; then
        echo "The file $line doesn't exist. Continuing with the next file..." >> $mailcontents
        echo "============" >> $mailcontents 
        continue
    else
        last_mod_time=$(stat -c '%Y' $line) # this line checks the log's last modification time and converts it to Unix's epoch
        last_24_hours=$(date +%s -d "24 hours ago") # this line returns the epoch for the current timestamp minus 24 hours

        if [ $last_mod_time -lt $last_24_hours ]; then
            echo "Log $line has NOT been updated in the last 24 hours" >> $mailcontents
        else
            echo "Log $line was updated during the last 24 hours" >> $mailcontents
        fi
    
        tail -100 $line > mylog.txt

        error=$(grep ERROR mylog.txt | wc -l) # We look for the lines containing the word "ERROR" in the mylog.txt file.
                                             # Then we redirect the output to the wc -l command that will count the number
                                             # of lines where the word ERROR appears.
    
        if [ $error -gt 0 ]; then # If this condition is satisfied, that means the word ERROR appeared at least once in
                                  # the log that's being examined in the current loop.
            echo "ERROR found in log $line" >> $mailcontents
        else
            echo "No errors found in $line" >> $mailcontents
        fi
    fi
echo "============" >> $mailcontents
done < mylogs.txt

if [ -s $mailcontents ]; then
    mail -s "Log errors and last modification times - $(date +'%A %B %d, %Y')" myemail@gmail.com < $mailcontents
fi

rm $mailcontents mylog.txt # Delete auxiliary files when we're done.

last_mod_time=$(stat -c '%Y' $line)
last_24_hours=$(date +%s -d "24 hours ago")