Linux terminal 101

List of commonly used (yet forgotten) Linux terminal commands:

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• Prints certain LSB (Linux Standard Base) and Distribution information.

  lsb_release -a

• command-line utility for Unix and Unix-like operating systems whose primary purpose is to convert and copy files. Example below will restores a hard disk drive (or an SD card, for example) from a previously created image.

  dd if=system.img of=/dev/sdc bs=4096 conv=noerror 

• Print certain system information

  uname

• Queries, installs, removes, and maintains Debian software packages and their dependencies.

  dpkg

  The primary and more user-friendly front-end for dpkg is aptitude. dpkg itself is controlled entirely via command line parameters, which consist of exactly one action and zero or more options. The action-parameter tells dpkg what to do and options control the behavior of the action in some way. dpkg can also be used as a front-end to dpkg-deb and dpkg-query. The list of supported actions is below (in the "Actions" section). If any such action is encountered dpkg just runs dpkg-deb or dpkg-query with the parameters given to it, but no specific options are currently passed to them, to use any such option the back-ends need to be called directly.

Hands on Android Development

First touch on Android development. 

First series of Android Development log.

Desktop Environment : Ubuntu 12.04 LTS, Android Development Tools 22.6.3, Android Developer Tools 22.3.0.
Device : HTC Butterfly, Android 4.3 (Jelly Bean).

Unable to update sites on ADT

Solution : remove sl4j.jar related from <java library>

Device not detected in ADT

Enable debug mode on device. Quote from android developer official site :

Note: On Android 4.2 and newer, Developer options is hidden by default. To make it available, go to Settings > About phone and tap Build number seven times. Return to the previous screen to find Developer options.

Ubuntu 12.04 : how to set up an NTP server

http://ubuntuforums.org/showthread.php?t=862620

Development Setup Ubuntu 12.04 TLS

Install MySQL Workbench

http://dev.mysql.com/downloads/workbench/5.2.ahtml

Install Ubuntu 12.04 LTS on HP Envy preloaded Win 8

Objective : Install Freedom Fone (Ubuntu 12.04 LTS based) to HP Envy preloaded with Win 8.

Create empty partition in existing Windows 8

• Disable UEFI in BIOS, enable legacy boot
• Run

  compmgmt.msc

  . Select something like 'device' or 'partition'
• Shrink existing partition
• Create empty partition

Install Ubuntu

• Run Disk Utility
• Make sure the install target partition has label like Create New Partition
• Run system from liveDVD / live USB, not directly install
• Run Install to Hardisk. This icon already appears on desktop
• Restart computer

Troubleshooting

DNS does not work

Can't nslookup, but able to ping external IP address. Solution: sudo service network-manager restart

Solution #2 : Configure name server lookup

ubuntuforums.org or tldp.org

Unavailable wireless card

Fixed from http://ubuntuforums.org/showthread.php?t=2035902&page=2. Download from http://linuxwireless.org/en/users/Download#Directly_downloading_the_tarball, then cd Desktop/compat-wireless-2012-05-10 &ls;––or whatever version was extracted, if not 2012-05-10 sudo su ./scripts/driver-select ath9k make make install exit

Booting from Ubuntu

• Press escape immediately after turning computer on
• Press F9 for Booting Options
• Select something boot from hardisk
• Select Ubuntu :D

Finish

Development Setup on Fedora 16

Install Apache Web Server

yum groupinstall "Web Server"

Apache Configuration

Install graphical interface for Apache configuration

yum install system-config-httpd

System configuration tool then need to be ran as root :

/usr/bin/system-config-httpd

or you can configure Apache server manualy :

vim /etc/httpd/conf/httpd.conf
vim /etc/httpd/conf.d/README

source : http://hacktux.com/fedora/apache

Troubleshooting

On Fedora you can run the following command which should give you the full error message :

/usr/sbin/httpd -t

The -t flag runs a syntax check on the configuration files so if there are any syntax errors there then this should help.

Fedora 16 installation on Dell Inspiron N5030

Objective : troubleshoot all hardware & configurations problems occured when installting Fedora 16 on Dell Inspiron N5030 laptop.

Environment : Fedora 16 64 bit on Dell Inspiron N5030

Wireless Network

problem : wireless connection is not detected
solution : Find wireless network card specification & download driver.

Install Repository

Enable repository access using command line for Fedora 15 & 16 :

su -c 'yum localinstall --nogpgcheck http://download1.rpmfusion.org/free/fedora/rpmfusion-free-release-stable.noarch.rpm http://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-stable.noarch.rpm'

source : http://developify.wordpress.com/2011/08/12/activate-broadcom-sta-wireless-driver-in-fedora-14
http://rpmfusion.org/Configuration

install broadcom-wl and the appropriate kmods all at the same time in a single yum or rpm command.

Activate Broadcom STA wireless driver

Touchpad Setting

problem : tap on touchpad as mouse click is not working

Keyboard Layout

problem : wrong keyboard layout, displayed characters not exactly matched the clicked keys.
solution : change Keyboard layout based on prefered layout.
System>Preferences>Keyboard>Layouts, "Add", "Choose a Layout" select "By Language" tab, Language: "English (US)".

Problem with MySQL - socket error

Problem : cant connect to mysql.
Error message : "Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock'"

Failed Attemps :
1. restart mysql service
2.

sudo mkdir /var/run/mysqld/
//Create the file by “touching” it.
sudo touch /var/run/mysqld/mysqld.sock
//Set the ownership of the mysqld.sock file and folder to mysql.
sudo chown -R mysql /var/run/mysqld/

source : http://anthologyoi.com/computers/cant-connect-to-local-mysql-server-through-socketerror.html

solution :
source : http://bikramkawan.com.np/error-2002-hy000-cant-connect-to-local-mysql-server-through-socket-varrunmysqldmysqld-sock-2/

SSH on Ubuntu

Location : ASEAN Foundation
Objective : set up SSH server on 192.1681.8, so it can be accessed from 10.0.0.126.

Process

check :
iptables configuration
file : /etc/ssh/ssh_config

Solution : use port 2222, not 22

#ssh localhost -p 2222

additional

Log in as root in ubuntu :

# sudo passwd

install tomcat6 on ubuntu 11.04 - the Natty Narwhal

sudo apt-get install tomcat6

source : https://help.ubuntu.com/11.04/serverguide/C/tomcat.html

httpd SELinux Policy documentation

SELinux policies, especially for httpd service, is still a delicate thing for me :(
Found a good site explaining the 8 policies in FedoraProject.

We will discuss the SELinux policies someday :D

Apache PHP deployment in Ubuntu

Environment : Linux Ubuntu 11.04 Natty Narwhal

php.ini-s packaged : development and production

php.ini-development and php.ini-production, which come with the PHP 5.3 package, are really just examples of recommended settings. You should review the settings and make sure that they apply to your use and copy them to the regular php.ini file location. On my Ubuntu 10.04.1 LTS (lucid) server, here’s where I find mine:

# locate php.ini-development
/usr/share/doc/php5-common/examples/php.ini-development

The alternative example, php.ini-production, is in the same directory.

source : http://serverfault.com/questions/178270/where-is-php-ini-development-on-ubuntu-lamp

Enable mod_rewrite

what is mod_rewrite?
mod_rewrite is a part of Apache server that can rewrite requested urls on the fly.

To enable mod_rewrite in Ubuntu, you just need to write this command in terminal

sudo a2enmod rewrite

Next thing is Apache needs to be restarted

sudo service apache2 restart

source : http://mahmudahsan.wordpress.com/2008/07/06/ubuntu-enable-mod_rewrite-in-apache-server/

Install - enable mcrypt

Also on Ubuntu, make sure you actually have php5-mcrypt installed. You can install it with:

sudo apt-get install php5-mcrypt

If you get any errors, you may need to enable the 'universe' repository, explained here:
https://help.ubuntu.com/community/Repositories/Ubuntu

source : http://php.net/manual/en/mcrypt.setup.php

Unable to lock the administration directory

After execute command :

sudo apt-get install php5-mcrypt

Error message appear :

E: Could not get lock /var/lib/dpkg/lock - open (11: Resource temporarily unavailable)
E: Unable to lock the administration directory (/var/lib/dpkg/), is another process using it?

Answer :
As per the other answers there is a package management app holding the lock. When unsure do not manually remove the lock, first run:

sudo fuser -cuk /var/lib/dpkg/lock; sudo rm -f /var/lib/dpkg/lock

This will kill any processes opening the file before removing it.

source : http://askubuntu.com/questions/15433/fixing-could-not-get-lock-var-lib-dpkg-lock

Install PEAR

PEAR is PHP’s equivalent of Perl’s CPAN. It offers hundreds of ready-to-use code modules that can make projects go much more quickly than having to hand code everything. However, it never seems like PEAR is easy to get running.
Installing the Needed Software

In Ubuntu, installing the following packages will quickly get you started with PEAR: php5-cli, php5-dev, and php-pear.

Make sure that you read the next section about problems with using PEAR to install PEAR packages if you are running 9.10, Karmic Kaola.

Here’s an example of how to quickly install those packages from the terminal.

$ sudo apt-get install php5-cli php5-dev php-pear
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following extra packages will be installed:
autoconf autoconf2.13 automake automake1.4 autotools-dev libltdl-dev libssl-dev libtool m4 php5-common shtool zlib1g-dev
Suggested packages:
autobook autoconf-archive gnu-standards autoconf-doc gettext libtool-doc automaken gfortran fortran95-compiler gcj php5-suhosin
The following NEW packages will be installed:
autoconf autoconf2.13 automake automake1.4 autotools-dev libltdl-dev libssl-dev libtool m4 php-pear php5-cli php5-common php5-dev shtool zlib1g-dev
0 upgraded, 15 newly installed, 0 to remove and 5 not upgraded.
Need to get 0B/8,690kB of archives.
After this operation, 27.7MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Selecting previously deselected package m4.
(Reading database ... 127272 files and directories currently installed.)
Unpacking m4 (from .../archives/m4_1.4.13-2_i386.deb) ...
...

source : http://chrisjean.com/2009/11/02/use-php-pear-with-ubuntu/

XSL with PHP in Ubuntu

XSL support in php5 is deactivated by default. Go to Synaptic Package Manager and search for php5-xsl. Mark the package for installation, apply the changes and once it’s finished, don’t forget to restart the server!

sudo /usr/sbin/apache2 -k restart

More XSL stories later on… time to experiment :)

source : http://soledadpenades.com/2006/12/09/xsl-with-php-in-ubuntu/