Install ubuntu 14.04

check ubuntu version

root@cory:~# lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 14.04 LTS
Release:	14.04
Codename:	trusty

add appdev user

root@cory:~# useradd -m appdev
root@cory:~# useradd -m -d /home/appdev appdev
root@cory:~# passwd appdev
su appdev

• sudo with no passwd

shell> su 
shell> chmod +w /etc/sudoers
shell> echo '${username} ALL=(ALL) NOPASSWD:ALL' >> /etc/sudoers
shell> chmod -w /etc/sudoers
shell> exit

stop default apache2

 root@cory:~# /etc/init.d/apache2 stop  
 * Stopping web server apache2

fix /etc/sudoers error

• I change /etc/sudoers file cause some error like:

 >>> /etc/sudoers: syntax error near line 30 <<<

• for fix , run as root , then fix the /etc/sudoers file

>pkexec su
>vi /etc/sudoers file

add alias for root

• check current user alias

 yufei@yufeidesktop:~$ alias
alias alert='notify-send --urgency=low -i "$([ $? = 0 ] && echo terminal || echo error)" "$(history|tail -n1|sed -e '\s/^\s*[0-9]\+\s*//;s/[;&|]\s*alert$//'\)"'
alias egrep='egrep --color=auto'
alias fgrep='fgrep --color=auto'
alias grep='grep --color=auto'
alias l='ls -CF'
alias la='ls -A'
alias ll='ls -alF'
alias ls='ls --color=auto'

• pkexec su - change to root

pkexec su
vi /root/.bashrc

you can find follow line

if [ -f ~/.bash_aliases ]; then
   . ~/.bash_aliases
fi

• create .bash_aliases , add the alias content to it.

install .deb package

• To install a downloaded Debian (Ubuntu) package

sudo dpkg -i packagename.deb

• To remove a Debian (Ubuntu) package (.deb)

sudo dpkg -r packagename

• To Reconfigure/Repair an installed Debian (Ubuntu) package

sudo dpkg-reconfigure packagename

apt-get

sudo apt-get install -f libavahi-compat-libdnssd1
sudo dpkg -i synergy-v1.7.4-stable-c734bab-Linux-x86_64.deb