R plot png file on centos

Problem:

 When you run R on in primary centOS server, you didn't use the png. It will appear some error "Error in X11...unable to start device PNG".  "

"unable to open connection to X11 display "

Solution:
Install the package
{code}
>yum install libpng-devel.x86_64
{code}

{code}
R
# To avoid the x11 warning
Sys.setenv("DISPLAY"=":0.0")
{code}




Reference:
Install libpng package
Check the png Capabilities of R
R with x11 setting

R package install method

Currently, I only try the local method

For example install HSAUR: A Handbook of Statistical Analyses Using R package

1. Download the package from the cran HSAUR_1.3-0.tar.gz
2. R
>install.packages(file_name_and_path, repos = NULL, type="source")


Reference: How to install R package 
the possible method from network 

Null hypothesis

Chineses:
假設檢定 Hypothesis Testing
假設測定Ι Document File

Student t test

For chinese Reference:
Simple view
Detail content

linux grep color setting

1. Solution
alias grep_gray="GREP_COLOR='1;30' grep --color=always"
alias grep_red="GREP_COLOR='1;31' grep --color=always"
alias grep_green="GREP_COLOR='1;32' grep --color=always"
alias grep_yellow="GREP_COLOR='1;33' grep --color=always"
alias grep_blue="GREP_COLOR='1;34' grep --color=always"
alias grep_magenta="GREP_COLOR='1;35' grep --color=always"
alias grep_cyan="GREP_COLOR='1;36' grep --color=always"

2. Example
echo hello there | grep_magenta ll | grep_yellow ere
hello there



Reference:
detail
linux color tutorial

Centos linux etc system config

1. Introduction

This is the nerve center of your system, it contains all system related configuration files in here or in its sub-directories. A "configuration file" is defined as a local file used to control the operation of a program; it must be static and cannot be an executable binary. For this reason, it's a good idea to backup this directory regularly. It will definitely save you a lot of re-configuration later if you re-install or lose your current installation. Normally, no binaries should be or are located here. [detail]

2. Category

[Network]
Firewall:  /etc/sysconfig/iptables , service iptable restart
DNS server: /etc/resolv.conf


[File System]
Files system: /etc/fstab, mount -a
Auto mount: /etc/auto.mnt, /etc/auto.master, service autofs restart

Javascript detect browser type

1. Problem:

Sometimes there are different present in the different browser, especially in IE and firefox-like. In this we should get the browser type and do the different method

2. Solution

/* To get the browser type */
function detectIsIEBrowser(){
    var isIE = false;
    var val = navigator.userAgent.toLowerCase();
   
    if(val.indexOf("msie") > -1) {
        isIE = true;
    }
    return isIE;
   
}




Reference
Basic
Advance_PPK