I don't care that much for other software. Linux is more than a kernel or an operating system. It is a symbol money does not rule everything. You don't pay for Linux. You don't have to watch ads when using it. In return, please be a little more friendly and tolerant to the people who build it. While Linux is built by professionals today, there is more heart and soul poured into it than in other operating systems.

http://beza1e1.tuxen.de/my_linux_history.html

3 steps to install percona utility...

yum install perl-DBI perl-Data-Dumper perl-DBD-MySQL

wget percona.com/get/pt-show-grants 

perl pt-show-grants -h 1.2.3.4 -uroot -pPasswd

Here is following commands to clear unwanted stuff from the /tmp partition on the server?

tmpwatch –mtime –all 48 /tmp

The above command will remove all files and folders from the /tmp which have not been accessed in the last couple of days (24×2=48). You can modify the number of hours as required.

If you need to change your server clock to another timezone for e.g. (Indian Standard Time), you can do so by modifying the /etc/localtime file:

mv /etc/localtime /etc/localtime.bak

ln -s /usr/share/zoneinfo/Asia/Calcutta /etc/localtime

If you have root access to the server then open the file /etc/aliases in your favorite editor. Look for the section Person who should get root mail and make the change as required.

vim /etc/aliases

Person who should get root’s mail  ##
root:   info@unixserveradmin.com

Instead of the first five fields, you can use any one of eight special strings. It will not just save your time but it will improve readability.

Special string    Meaning
@reboot ——> Run once, at startup.
@yearly ——> Run once a year, “0 0 1 1 *”.
@annually –> (same as @yearly)
@monthly —> Run once a month, “0 0 1 * *”.
@weekly —–> Run once a week, “0 0 * * 0″.
@daily ——–> Run once a day, “0 0 * * *”.
@midnight –> (same as @daily)
@hourly —–> Run once an hour, “0 * * * *”.

For e.g. run ntpdate every hour:
@hourly /path/to/ntpdatevim /etc/ssh/sshd_config

This is a sample shell script while loop

while read mydb
do
echo "time scp /home/backup/mysql/$mydb/ticket.txt.gz 1.2.3.4:/tmp/$mydb.txt.gz "
done << dblist
akolaII
akol
ako
dblist

grep "error" error_log |awk -F[ {'print $4'} \
| sort | sed -e 's/]//g' | grep -v "/var/www/html/" \
| grep -v "/usr/local/src/code" | awk {'print $2'} \
| grep -v "75.142.246.205" |uniq | awk -F. {'print $1"."$2"."$3"/24"'} |uniq

114.80.93/24
119.63.193/24
124.115.0/24
205.234.253/24

date -d"-1 day ago" +'%b%d'

equals to

mysql -Bse"select date_format(date(date_add(now() , interval 1 day)),'%b%d')"

Use this command to convert private key to public key.

ssh-keygen -y -f dec15a.pem > dec15a.pub

Now upload the new public key to list of keys on Amazon so that you can connect to your instances in that region using the same pem key.