Using Git With Multiple SSH Keys and Accounts

Generating SSH keys for GitHub

Here are github account and work account.

• GitHub:
  SSH Key: github_id_rsa
  Account: oopsmonk

• Work:
  SSH Key: work_id_rsa
  Account: SamChen

Add SSH config File

Modify ~/.ssh/config

# Default github
Host github.com
    HostName github.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/github_id_rsa

# Work git server
Host work.gitserver.com
    HostName work.gitserver.com
    PreferredAuthentications publickey
    IdentityFile ~/.ssh/work_id_rsa

Git Repository Configuation

• GitHub Project:

  $ git clone https://github.com/abc/projectA.git  
  $ cd projectA
  #github account
  $ git config user.name "oopsmonk"
  $ git config user.email "oopsmonk@example.com.tw"

• Working Project:

  $ git clone https://work.com.tw/repo/projectW.git  
  $ cd projectW
  #working account
  $ git config user.name "SamChen"
  $ git config user.email "SamChen@example.com.tw"

Now you can deal with git repositories using different accounts.

(Additional) Using ssh-agent to access GitHub without password

Check key list

# No ssh-agent running 
$ ssh-add -l
Could not open a connection to your authentication agent.
$  

Enable ssh-agent (Ubuntu12.04):

#enable ssh-agent
$ eval `ssh-agent -s`

#add keys to agent
$ cd ~/.ssh
$ ssh-add work_id_rsa github_id_rsa
Identity added: work_id_rsa (work_id_rsa)
Identity added: github_id_rsa (github_id_rsa)

#list added keys
$ ssh-add -L

#delete keys in agent  
$ ssh-add -D

Now you can commit modifications to git repository without password.

Reference:
Understanding ssh-agent and ssh-add
How can I run ssh-add automatically, without password prompt?

Redirect and Save iptables on Ubuntu 12.04

Redirect port 8080 to 80

sudo iptables -t nat -A PREROUTING -p tcp --dport 80 -j REDIRECT --to-port 8080  

Check iptables setting

sudo iptables -t nat -L  

Save configure to iptables.rules

sudo iptables-save > /etc/iptables.rules  

Save Solution #1

Configre /etc/network/interfaces

iface eth0 inet dhcp  
    pre-up iptables-restore < /etc/iptables.rules  

Save Solution #2

Configure /etc/network/if-pre-up.d/iptablesload

#!/bin/sh
iptables-restore < /etc/iptables.rules
exit 0

Configure /etc/network/if-post-down.d/iptablessave

#!/bin/sh
iptables-save -c > /etc/iptables.rules
if [ -f /etc/iptables.downrules ]; then
    iptables-restore < /etc/iptables.downrules
fi
exit 0

Change permissions

sudo chmod +x /etc/network/if-post-down.d/iptablessave  
sudo chmod +x /etc/network/if-pre-up.d/iptablesload  

Reference:
Tomcat: redirecting traffic from port 8080 to 80 using iptables
IptablesHowTo

Install JDK1.4.2(32bit) on Ubuntu 12.04 LTS(64bit)

Here is an error occurred if installed directly:
install.sfx.XXX: not found

Solution:

• install g++-mltilib and JDK

  $ sudo apt-get install g++-multilib  
  $ chmod +x j2sdk-1_4_2_19-linux-i586.bin  
  $ ./j2sdk-1_4_2_19-linux-i586.bin
  .....
  Do you agree to the above license terms? [yes or no]
  yes
  Unpacking...
  Checksumming...
  0
  0
  Extracting...
  UnZipSFX 5.40 of 28 November 1998, by Info-ZIP (Zip-Bugs@lists.wku.edu).
     creating: j2sdk1.4.2_19/
     creating: j2sdk1.4.2_19/jre/
     creating: j2sdk1.4.2_19/jre/bin/
    inflating: j2sdk1.4.2_19/jre/bin/java
    inflating: j2sdk1.4.2_19/jre/bin/keytool
    inflating: j2sdk1.4.2_19/jre/bin/policytool
  ....
  Creating j2sdk1.4.2_19/lib/tools.jar
  Creating j2sdk1.4.2_19/jre/lib/rt.jar
  Creating j2sdk1.4.2_19/jre/lib/jsse.jar
  Creating j2sdk1.4.2_19/jre/lib/charsets.jar
  Creating j2sdk1.4.2_19/jre/lib/ext/localedata.jar
  Creating j2sdk1.4.2_19/jre/lib/plugin.jar
  Creating j2sdk1.4.2_19/jre/javaws/javaws.jar
  Done.  
  $ sudo mkdir -p /usr/lib/jvm  
  $ sudo mv j2sdk1.4.2_19 /usr/lib/jvm/java-1.4.2_19

• Java environment configuration.

  $ wget http://webupd8.googlecode.com/files/update-java-0.5b  
  $ chmod +x update-java-0.5b
  $ sudo ./update-java-0.5b  

  Select java-1.4.2_19
  

  Check java version

  $ java -version
  java version "1.4.2_19"
  Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_19-b04)
  Java HotSpot(TM) Client VM (build 1.4.2_19-b04, mixed mode)