This simple bash script checks your current public IP and compares it to the previous days public IP (depending on cron job). Email alert is sent if IP has changed.

Credit goes to Ronny Bull – http://ronnybull.com/2011/08/10/bash-dynamic-public-ip-address-monitor-script/

Pre-req – install curl and postfix

apt-get install curl
apt-get install postfix

Bash script:

Simple bash script to remove duplicate rows from a table:

#!/bin/bash
echo "Remove duplicate records from tbl_duplicates"
mysql -uusername -ppassword database -e "DELETE n1 FROM tbl_duplicates n1, tbl_duplicates n2 WHERE n1.col_id > n2.col_id AND n1.col_duplicate = n2.col_duplicate;"

Terms mentioned:

tbl_duplicates – table to remove duplicates from
col_id – column ID
col_duplicates – a column which contains duplicate data
> – this keeps the row with the lowest id

Simple script to verify that MySQL replication is working:

*Script is setup on slave server

#!/bin/bash
# Originally from http://lists.mysql.org/replication/1672
# Checks MySQL Replication status. Sends user(s) a notification of status
status=0
MasterHost="10.10.10.10"
SlaveHost="127.0.0.1"
emails="user@email.com" #multiple emails space separated
DownSubject="Replication status - Down"
GoodSubject="Replication status - Good"
GoodMessage="Everything regarding MySQL replication on $SlaveHost is good.nHave a great day!nn"

#Grab the lines for each and use Gawk to get the last part of the string(Yes/No)
SQLresponse=`mysql -u root --password=password dbname -e "show slave status G" |grep -i "Slave_SQL_Running"|gawk '{print $2}'`
IOresponse=`mysql -u root --password=password dbname -e "show slave status G" |grep -i "Slave_IO_Running"|gawk '{print $2}'`

if [ "$SQLresponse" = "No" ]; then
error="Replication on the slave MySQL server($SlaveHost) has stopped working.nSlave_SQL_Running: Non"
status=1
fi

if [ "$IOresponse" = "No" ]; then
error="Replication on the slave MySQL server($SlaveHost) has stopped working.nSlave_IO_Running: Non"
status=1
fi

# If the replication is not working
if [ $status = 1 ]; then
for address in $emails; do
echo -e $error | mail -s "$DownSubject" $address
echo "Replication down, sent email to $address"
done
fi

# If the replication is working fine
if [ $status = 0 ]; then
for address in $emails; do
echo -e $GoodMessage | mail -s "$GoodSubject" $address
echo "Replication is up, still sent email to $address"
done
fi

The below bash script, when executed, will check the % of disk space usuage of the complete filesystem and email a specified email address if more than 80% full.

Pre-req – create fs_report.log inside /var/log/

i.e.

 
touch /var/log/fs_report.log 

Create a new bash script:

 
vim /path/to/script/diskspace.sh 

Replace the email address or modify the disk space below as needed:

#!/bin/bash
#
#Extract % use for the filesystem
#Send email warning to if the raid is 80% or more full
#Include Folder/File sizes of the filesystem directory contents
#
df -h | awk '{ print $5 }' | cut -d'%' -f1 | while read usep; do
if [ $usep -ge 80 ]; then
echo "***$(hostname) is $usep% FULL at $(date)" > /var/log/fs_report.log
echo "***Please remove unnecessary data from $(hostname)" >> /var/log/fs_report.log
echo "***Detailed Folder/File size for BackupServer content:" >> /var/log/fs_report.log
df -h >> /var/log/fs_report.log
mail -s "WARNING-bksvr2 $usep% FULL" backup@mydomain.com < /var/log/fs_report.log -- -f "backup@mydomain.com"
fi
done

*Make sure to make the script executable:

chmod +x diskspace.sh

To automate this script add a cron job to run it on a regular basis:

0 8 * * * /path/to/script/diskspace.sh

The above cron job will run the script at 8am everyday.