Shell Programming and Scripting

/var/log/mail.log
/var/log/some.log
.
.
.
/var/log/some_other.log

#!/bin/bash
mailcontents=mailbody
while read line
do
    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
        echo "============" >> $mailcontents
    else
        echo "Log $line was updated during the last 24 hours" >> $mailcontents
        echo "============" >> $mailcontents
    fi
    
    tail -100 $line > checklog

    error=$(cat checklog | grep ERROR | wc -l)
    if [ $error -gt 0 ]; then
        echo "ERROR found in log $line" >> $mailcontents
    fi

done < mylogs

if [ -s $mailcontents ]; then
    mail -s "Log errors and last modification times" youremail@yourdomain.com < $mailcontents
fi

rm $mailcontents checklog

while read line
do
[...bunch of commands here :) ...]
done < Logcheck.txt

tail -100 /var/log/mail.log > checklog

#!/bin/bash
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 > checklog

        error=$(grep ERROR checklog | wc -l) # We look for the lines containing the word "ERROR" in the checklog 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

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

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

echo -e "\t" $(grep ERROR checklog) >> $mailcontents

echo "ERROR found in log $line" >> $mailcontents