Set up git:

yum install git-core
cd ~/.ssh
ssh-keygen -t rsa -C "shantanu.oak@gmail.com"

Contents of the file "id_rsa.pub" should be copied to gitHub site.
On the GitHub site Click “Account Settings” > Click “SSH Public Keys” > Click “Add another public key”

This will allow passwordless access to github site:
ssh -T git@github.com
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Global setup:

git config --global user.name "Shantanu Oak"
git config --global user.email shantanu.oak@gmail.com
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Next steps:

mkdir syllabalize_unicode
cd syllabalize_unicode
git init
touch README
git add README
git commit -m 'first commit'
git remote add origin git@github.com:shantanuo/syllabalize_unicode.git
git push -u origin master
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Existing Git Repo?

cd existing_git_repo
git remote add origin git@github.com:shantanuo/syllabalize_unicode.git
git push -u origin master
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clone (download) the source
git clone git@github.com:ahiguti/HandlerSocket-Plugin-for-MySQL.git
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Install MySQL

mkdir download
cd download
wget http://files.directadmin.com/services/all/mysql/64-bit/5.5.20/MySQL-client-5.5.20-1.linux2.6.x86_64.rpm
wget http://files.directadmin.com/services/all/mysql/64-bit/5.5.20/MySQL-devel-5.5.20-1.linux2.6.x86_64.rpm
wget http://files.directadmin.com/services/all/mysql/64-bit/5.5.20/MySQL-server-5.5.20-1.linux2.6.x86_64.rpm
wget http://files.directadmin.com/services/all/mysql/64-bit/5.5.20/MySQL-shared-5.5.20-1.linux2.6.x86_64.rpm

The commands are as follows:

rpm -iUh *

After installing mysql shared compact library, this was working as expected

wget ftp://ftp.isu.edu.tw/pub/Unix/Database/MySQL/Downloads/MySQL-5.5/MySQL-shared-compat-5.5.24-1.el6.x86_64.rpm
rpm -ihv MySQL-shared-compat-5.5.24-1.el6.x86_64.rpm
yum install php-mysql --skip-broken

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Here is how it can be achieved using remi or epel

/usr/bin/wget http://rpms.famillecollet.com/enterprise/remi-release-6.rpm
/bin/rpm -Uvh *.rpm
/usr/bin/yum install --enablerepo=remi mysql-server.x86_64*

Using epel:

wget http://download.fedoraproject.org/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm
rpm -Uvh epel-release-5-4.noarch.rpm
yum install python26

Tunneling an ssh connection through an ssh connection is completely lawful, but you need to pick unused ports for your forwarding listeners.

ssh user@100.100.100.100 -L 2201:192.168.25.100:22

then
ssh localhost -p 2201

You should end up on server B (unless something's already bound to local:2201, in which case, pick another port).
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There are times when you need to connect to a remote server through some other server. You can skip logging to an intermediate server and connect directly to remote server using SSH like this...

ssh -t -t root@192.168.1.1 "ssh -i /root/remote_server.pem ec2-1-2-3-4.compute-1.amazonaws.com"

To upload the cron job from a file to another user, combine it with -u option.

# crontab -u root /home/oracle/mycronjobs.txt

Divides the buffer pool into a user-specified number of separate regions, each with its own LRU list and related data structures, to reduce contention during concurrent memory read and write operations. The size specified by innodb_buffer_pool_size is divided among all the buffer pool instances. For best efficiency, specify a combination of innodb_buffer_pool_instances and innodb_buffer_pool_size so that each buffer pool instance is at least 1 gigabyte.

log a command to console and to 2 files separately stdout and stderr

# command > >(tee stdout.log) 2> >(tee stderr.log >&2)
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Real full backup copy of /etc folder
# rsync -a /etc /destination

If your repository is available on a server for e.g. 10.10.10.6, you need to point it to that server in your config file.

# cat /etc/yum.repos.d/rhel.repo
[base]
name=RHEL 5 $releasever - $basearch - Base
baseurl=http://10.10.10.6/yum/rhel/5/base/
enabled=1
gpgcheck=0

If the internet is not working from a server, you need to change one file.

cat /etc/resolove.conf

nameserver 8.8.8.8
nameserver 10.10.10.1
nameserver 10.10.10.6

/etc/init.d/network restart

The mail command will not work if the internet is down.

If you need fresh mysql installation you need to run script to create default mysql database and system tables. The script is called "mysql_install_db" and is either in the bin or in scripts directory of your mysql installation. Change the my.cnf to reflect new datadir and run mysql_install_db for it to create mysql database and system tables in the new datatir and then start mysqld_safe.

The mysql general logs use the following date format to display current date.

date '+%y%m%d %H:%M:%S'

The same can be used in the shell script to echo date at the beginning of the line.

If you want someone to access all the files and locations that mysql has access to, then add the username to the mysql group.

vi /etc/group

mysql:x:27:santosh