List the installed packages on your Ubuntu box

I found out how to do this recently and thought it might be helpful to some people. To output this information to a file in your home directory you would use,

CODE:
dpkg --get-selections > installed-software

And if you wanted to use the list to reinstall this software on a fresh ubuntu setup,

Code:

dpkg --set-selections < installed-software

followed by

Code:

dselect

How to get rid of spaces in file names

for file in *\ * ; do mv "${file}" "${file// /_}" ; done

Rotate / Delete log files using logrotate.d

http://www.watchingthenet.com/how-to-manage-log-file-size-archive-deletion.html

Use ISO images via script

http://www.ubuntugeek.com/mount-and-unmout-iso-images-without-burning-them.html

How to update your system via Terminal

Setting up a cron job to do updates on a regular basis is simple to do using the command,


sudo aptitude full-upgrade

How Do I Enable Remote Access To MySQL Database Server?

How Do I Enable Remote Access To MySQL Database Server?

By default, MySQL database server remote access disabled for security reasons. However, some time you need to provide the remote access to database server from home or from web server.
MySQL Remote Access

You need type the following commands which will allow remote connections:
Step # 1: Login over ssh if server is outside your IDC

First, login over ssh to remote MySQL database server
Step # 2: Enable networking

Once connected you need edit the mysql configuration file my.cfg using text editor such as vi.

* If you are using Debian Linux file is located at /etc/mysql/my.cnf location
* If you are using Red Hat Linux/Fedora/Centos Linux file is located at /etc/my.cnf location
* If you are using FreeBSD you need to create a file /var/db/mysql/my.cnf

# vi /etc/my.cnf
Step # 3: Once file opened, locate line that read as follows

[mysqld]

Make sure line skip-networking is commented (or remove line) and add following line

bind-address=YOUR-SERVER-IP

For example, if your MySQL server IP is 65.55.55.2 then entire block should be look like as follows:
[mysqld]
user = mysql
pid-file = /var/run/mysqld/mysqld.pid
socket = /var/run/mysqld/mysqld.sock
port = 3306
basedir = /usr
datadir = /var/lib/mysql
tmpdir = /tmp
language = /usr/share/mysql/English
bind-address = 65.55.55.2
# skip-networking
....
..
....Where,

* bind-address : IP address to bind to.
* skip-networking : Don’t listen for TCP/IP connections at all. All interaction with mysqld must be made via Unix sockets. This option is highly recommended for systems where only local requests are allowed. Since you need to allow remote connection this line should removed from file or put it in comment state.

Step# 4 Save and Close the file

Restart your mysql service to take change in effect:# /etc/init.d/mysql restart
Step # 5 Grant access to remote IP address

# mysql -u root -p mysqlGrant access to new database
If you want to add new database called foo for user bar and remote IP 202.54.10.20 then you need to type following commands at mysql> prompt:mysql> CREATE DATABASE foo;
mysql> GRANT ALL ON foo.* TO bar@'202.54.10.20' IDENTIFIED BY 'PASSWORD';
How Do I Grant access to existing database?

Let us assume that you are always making connection from remote IP called 202.54.10.20 for database called webdb for user webadmin, To grant access to this IP address type the following command At mysql> prompt for existing database:mysql> update db set Host='202.54.10.20' where Db='webdb';
mysql> update user set Host='202.54.10.20' where user='webadmin';
Step # 5: Logout of MySQL

Type exit command to logout mysql:mysql> exit
Step # 6: Open port 3306

You need to open port 3306 using iptables or BSD pf firewall.
A sample iptables rule to open Linux iptables firewall

/sbin/iptables -A INPUT -i eth0 -p tcp --destination-port 3306 -j ACCEPT

OR only allow remote connection from your web server located at 10.5.1.3:

/sbin/iptables -A INPUT -i eth0 -s 10.5.1.3 -p tcp --destination-port 3306 -j ACCEPT

OR only allow remote connection from your lan subnet 192.168.1.0/24:

/sbin/iptables -A INPUT -i eth0 -s 192.168.1.0/24 -p tcp --destination-port 3306 -j ACCEPT

A sample FreeBSD / OpenBSD pf rule ( /etc/pf.conf)

pass in on $ext_if proto tcp from any to any port 3306

OR allow only access from your web server located at 10.5.1.3:

pass in on $ext_if proto tcp from 10.5.1.3 to any port 3306 flags S/SA synproxy state

Step # 7: Test it

From remote system or your desktop type the command:
$ mysql -u webadmin –h 65.55.55.2 –p
Where,

* -u webadmin: webadmin is MySQL username
* -h IP or hostname: 65.55.55.2 is MySQL server IP address or hostname (FQDN)
* -p : Prompt for password

You can also use telnet to connect to port 3306 for testing purpose:$ telnet 65.55.55.2 3306

Finding your Ubuntu version

Sometimes you ask others to help you resolve a problem, it is good to know which ubuntu version you have... here is the very useful command

cappetta@Linux-Box:/var/log/mysql$ lsb_release -dc
Description:    Ubuntu 7.10
Codename:       gutsy

cappetta@Linux-Box:/var/log/mysql$ cat /etc/issue
Ubuntu 7.10 \n \l

cappetta@Linux-Box:/var/log/mysql$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=7.10
DISTRIB_CODENAME=gutsy
DISTRIB_DESCRIPTION="Ubuntu 7.10"