2010-05-30

• [專案] ClassCloud-LiveCD : 基於 DRBL 的雲端教學環境

DRBL-Hadoop Live

• 如何在 shell script 裡面安裝 java 又不用選 yes
  • [參考] ​Installing java non-interactively
  • 這裡提到用 debconf-set-selections 來設定一些參數，讓 sun-java*-* 不問授權的 yes，方法包括有寫檔跟沒寫檔的做法，個人覺得留言裡面的那個做法最帥了!!

    cat << EOF | /usr/bin/debconf-set-selections
    sun-java6-bin   shared/accepted-sun-dlj-v1-1    select true
    sun-java6-jdk   shared/accepted-sun-dlj-v1-1    select true
    sun-java6-jre   shared/accepted-sun-dlj-v1-1    select true
    EOF
    

  • 那麼如果以後遇到別的套件也有類似的問題該怎麼找參數呢?? 答案是用 debconf-get-selections 這個指令，首先必須安裝 ​debconf-utils 套件，然後執行 debconf-get-selections 再用 grep 用套件名稱找出可以改的參數。

    ~$ sudo debconf-get-selections | grep sun-java6
    sun-java6-jre	sun-java6-jre/stopthread	boolean	true
    sun-java6-bin	shared/accepted-sun-dlj-v1-1	boolean	true
    sun-java6-jre	shared/accepted-sun-dlj-v1-1	boolean	true
    sun-java6-jre	sun-java6-jre/jcepolicy	note	
    sun-java6-bin	shared/error-sun-dlj-v1-1	error	
    sun-java6-jre	shared/error-sun-dlj-v1-1	error	
    sun-java6-bin	shared/present-sun-dlj-v1-1	note	
    sun-java6-jre	shared/present-sun-dlj-v1-1	note	
    

  • 須注意的是原本參數是 boolean 格式，若要下給 debconf-set-selections 必須置換成 select 關鍵字喔!!

    ~$ sudo debconf-get-selections | grep sun-java6 | grep boolean | sed 's#boolean#select#g'
    sun-java6-bin   shared/accepted-sun-dlj-v1-1    select  true
    sun-java6-jdk   shared/accepted-sun-dlj-v1-1    select  true
    sun-java6-jre   shared/accepted-sun-dlj-v1-1    select  true
    sun-java6-jre   sun-java6-jre/stopthread        select  true
    

Shell Script

• 如何在 shell script 裡面把標準輸入跟標準輸出重新導向到另一個路徑呢?!
  • [參考] ​Shell scripting: How to redirect output from within the script itself?

    #! /bin/bash
    
    TARGET="target-file"
    
    # file descriptor 4 prints to STDOUT and to TARGET
    exec 4> >(while read a; do echo $a; echo $a >>$TARGET; done)
    # file descriptor 5 remembers STDOUT
    exec 5>&1
    
    # now STDOUT is redirected
    exec >&4
    date
    
    # wer're done
    exec >&5
    echo "Date sent to fd4."