Disabling shutdown command for users 禁止一般使用者關機 linux kde

最近玩server發現一件嚴重的事情！！

一般使用者竟然可以執行
$ /sbin/shutdown -h now

Solution:
# ls -l /sbin/shutdown
lrwxrwxrwx 1 root root 14 May 26 14:07 /sbin/shutdown -> /bin/systemctl
# ls -l /bin/systemctl
-rwxrwxrwx 1 root root 538904 May 26 14:07 /bin/systemctl
# chmod 755 /sbin/shutdown
# ls -l /bin/systemctl
-rwxr-xr-x 1 root root 538904 May 26 14:07 /bin/systemctl

# vi /etc/kde4/kdm/kdmrc
搜尋所有AllowShutdown=ALL
改成AllowShutdown=Root

test 7

/*
  ReadAnalogVoltage
  Reads an analog input on pin 0, converts it to voltage, and prints the result to the serial monitor.
  Attach the center pin of a potentiometer to pin A0, and the outside pins to +5V and ground.

 This example code is in the public domain.
 */

const int ledPin =  13;      // the number of the LED pin

// Variables will change:
int ledState = LOW;             // ledState used to set the LED
long previousMillis = 0,abcMillis=0;        // will store last time LED was updated
unsigned long button=0;
int buttonflag=1;
int count=0,longflag=0;

Arduino practice 3

const int numReadings = 10;

int readings[numReadings];      // the readings from the analog input
int index = 0;                  // the index of the current reading
int total = 0;                  // the running total
int average = 0;                // the average
int brightness = 0;
int fadeAmount = 5;
int delayDuration = 30;
int flag=0;

Debian Jessie SSL VPN Client

目的：在學校網域以外的地方連老師的鏡像站
不知從何時開始學校外沒辦法連到老師的鏡像站
# ping 120.117.72.71

建立網路印表機伺服器 安裝網路印表機 智慧型手機列印 linux printer share windows linux smartphone tablet

測試環境在Linux上建網路印表機伺服器，讓電腦、手機與平板都可列印

Server
硬體架構：x86_64
O.S.:Linux Debian Jessie
印表機：Epson stylns TX235(USB port)

印表機的選擇

印表機廠牌有Epson、Hp等，每家廠牌又有各種型號，我們所要選擇廠牌與型號，當然是要能支援Linux，我們從Linux 基金會的 Open Printing來搜尋哪些印表機支援Linux，網址如下：
Open Printing 資料庫：http://www.openprinting.org/printers

Linux cpu temperature

# apt-get install lm-sensors
# sensors-detect
# sensors-detect revision 6209 (2014-01-14 22:51:58 +0100)
# Board: ASRock Z77 Extreme4

Doom on Linux Debian

# apt-get install prboom

Downloads Doom.wad
http://www.pc-freak.net/blog/doom-1-doom-2-doom-3-game-wad-files-for-download-playing-doom-on-debian-linux-via-freedoom-open-source-doom-engine/

Debian Jessie Cross Toolchains Install

安裝Cross-compiler分三個套件

armhf(ArmHardFloatPort)
Supported device:supports newer, more powerful 32-bit devices using ARMv7
armel(ArmEabiPort)
Supported device:port targets a range of older 32-bit devices using ARMv4, particularly those used in NAS hardware and a variety of *plug computers.
arm64(Arm64Port)
Supported device:latest 64-bit ARM-powered devices.
# dpkg --add-architecture armel
# apt-get update
# apt-get install crossbuild-essential-armel
紅色字可以替代armel armhf arm64 

# vi /etc/apt/sources.list.d/crosstools.list
deb http://emdebian.org/tools/debian/ jessie main
# cd /tmp
# wget http://emdebian.org/tools/debian/emdebian-toolchain-archive.key
# apt-get install curl
# curl http://emdebian.org/tools/debian/emdebian-toolchain-archive.key | apt-key add -
# apt-get update

install arm-linux-gnueabi- armel toolchain
# dpkg --add-architecture armel
# apt-get update
# apt-get install crossbuild-essential-armel
# arm-linux-gnueabi-
arm-linux-gnueabi-addr2line       arm-linux-gnueabi-gcc-nm
arm-linux-gnueabi-ar              arm-linux-gnueabi-gcc-nm-4.9
arm-linux-gnueabi-as              arm-linux-gnueabi-gcc-ranlib
arm-linux-gnueabi-c++             arm-linux-gnueabi-gcc-ranlib-4.9
arm-linux-gnueabi-c89             arm-linux-gnueabi-gcov-4.9
arm-linux-gnueabi-c99             arm-linux-gnueabi-gprof
arm-linux-gnueabi-cc              arm-linux-gnueabi-ld
arm-linux-gnueabi-c++filt         arm-linux-gnueabi-ld.bfd
arm-linux-gnueabi-cpp-4.9         arm-linux-gnueabi-ld.gold
arm-linux-gnueabi-dwp             arm-linux-gnueabi-nm
arm-linux-gnueabi-elfedit         arm-linux-gnueabi-objcopy
arm-linux-gnueabi-g++             arm-linux-gnueabi-objdump
arm-linux-gnueabi-g++-4.9         arm-linux-gnueabi-ranlib
arm-linux-gnueabi-gcc             arm-linux-gnueabi-readelf
arm-linux-gnueabi-gcc-4.9         arm-linux-gnueabi-size
arm-linux-gnueabi-gcc-ar          arm-linux-gnueabi-strings
arm-linux-gnueabi-gcc-ar-4.9      arm-linux-gnueabi-strip

if you whant to install armhf architecture
# dpkg --add-architecture armhf
# apt-get update
# apt-get install crossbuild-essential-armhf

Reference:https://wiki.debian.org/CrossToolchains

office word 2010 目錄製作、標題清單製作、樣式自訂、插入圖表標號、交互參照、插入參考文獻、自動產生目錄 圖目錄 表目錄

工具：office 2010 word

Linux Mplayer 測試 視訊攝影機 WebCam

# apt-get install mplayer

tv://<channel_name>
--tv=<option1:option2:...>
$ mplayer --tv=driver=help -vo help
MPlayer2 2.0-728-g2c378c7-4+b1 (C) 2000-2012 MPlayer Team
Available video output drivers:
        vdpau   VDPAU with X11
        xv      X11/Xv
        gl3     OpenGL 3.x
        gl      OpenGL
        x11     X11 ( XImage/Shm )
        sdl     SDL YUV/RGB/BGR renderer (SDL v1.1.7+ only!)
        caca    libcaca
        v4l2    V4L2 MPEG Video Decoder Output
        null    Null video output
        directfb        Direct Framebuffer Device
        yuv4mpeg        yuv4mpeg output for mjpegtools
        png     PNG file
        jpeg    JPEG file
        gif89a  animated GIF output
        tga     Targa output
        pnm     PPM/PGM/PGMYUV file
        md5sum  md5sum of each frame
        gl_nosw OpenGL no software rendering
$ ls /dev/video*
/dev/video0  /dev/video1
$ mplayer tv:// -tv driver=v4l2:width=640:height=480:device=/dev/video0

monitor brightness resolution setup linux

觀看目前monitor資訊
$ xrandr --current
Screen 0: minimum 320 x 200, current 1366 x 768, maximum 4096 x 4096
LVDS-0 connected 1366x768+0+0 (normal left inverted right x axis y axis) 222mm x 125mm
   1366x768      60.01*+
   1360x768      59.80    59.96 
   1024x768      60.04    60.00 
   960x720       60.00 
   928x696       60.05 
   896x672       60.01 
   960x600       60.00 
   960x540       59.99 
   800x600       60.00    60.32    56.25 
   840x525       60.01    59.88 
   800x512       60.17 
   700x525       59.98 
   640x512       60.02 
   720x450       59.89 
   640x480       60.00    59.94 
   680x384       59.80    59.96 
   576x432       60.06 
   512x384       60.00 
   400x300       60.32    56.34 
   320x240       60.05
DVI-0 disconnected (normal left inverted right x axis y axis)

調整螢幕亮度
$ xrandr --output LVDS-0 --brightness 0.8

調整螢幕解析度
$ xrandr -s 1366x768

0123H存於RAM：31H 30H（30H為低位元組），求某數的6.5倍，其結果存於31H~30H

Vision Control System

https://www.google.com.tw/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&cad=rja&uact=8&ved=0CDkQFjAE&url=http%3A%2F%2Fwww.openfoundry.org%2Ftw%2Fdownload%2Fdoc_download%2F960-&ei=85DwVJikPI_c8AXBp4GgAQ&usg=AFQjCNGE-0OVk2WP-8bsKD84BqAwTn9NlQ

http://blog.ez2learn.com/2011/10/20/taiwan-software-lacking-of-vcs/

https://ihower.tw/git/vcs.html

天體觀測 專有名詞解釋

解釋名詞

天球：（英語：Celestial sphere），是在天文學和導航上假想出的一個與地球同圓心，並有相同的自轉軸，半徑無限大的球。天空中所有的物體（星星）都可以當成投影在天球上的物件。地球的赤道和地理極點（非南北磁極）投射到天球上，就是天球赤道和天極（地球的自轉軸向天球延伸後，在無窮遠處與天球交會的兩個假想點。）。如果我們假設地球是不動的話，那麼正個天球將由東向西轉動，所以我們也就看到星星們東昇西落的現象。

https://tw.knowledge.yahoo.com/question/questionqid=1406072203309
http://zh.wikipedia.org/wiki/%E5%A4%A9%E7%90%83

http://zh.wikipedia.org/wiki/%E5%A4%A9%E7%90%83

LCD應用控制 8051 assembly

;------------------------------------------
;     ==================================
;     ==        LCD應用控制         ==
;     ==          2014/12/29          ==
;     ==        蘇偉諺 4A037052       ==
;     ==================================
;------------------------------------------
;於LCD顯示第二列顯示'THIS IS 2ND LINE'並閃爍三次，然後由左而右依序清除

LCD應用控制 8051 assembly

UART、LCD與4x4鍵盤應用

4x4按鍵與LCD應用 8051 assembly

喇叭與七段應用控制 8051 assembly