取得IPv6 address

參考資料：
get-ipv6-addr.c - Source file - www-user

sscanf使用心得

參考資料：
C 語言中的 sscanf() 函數

linux script

1. 判斷檔案是否存在

#!/bin/bash
file="/etc/hosts"
if [ -f "$file" ]
then
  echo "$file found."
else
  echo "$file not found."
fi

       -b FILE
              FILE exists and is block special
       -c FILE
              FILE exists and is character special
       -d FILE
              FILE exists and is a directory
       -e FILE
              FILE exists
       -f FILE
              FILE exists and is a regular file
       -g FILE
              FILE exists and is set-group-ID
       -G FILE
              FILE exists and is owned by the effective group ID
       -h FILE
              FILE exists and is a symbolic link (same as -L)
       -k FILE
              FILE exists and has its sticky bit set
       -L FILE
              FILE exists and is a symbolic link (same as -h)
       -O FILE
              FILE exists and is owned by the effective user ID
       -p FILE
              FILE exists and is a named pipe
       -r FILE
              FILE exists and read permission is granted
       -s FILE
              FILE exists and has a size greater than zero
       -S FILE
              FILE exists and is a socket
       -t FD  file descriptor FD is opened on a terminal
       -u FILE
              FILE exists and its set-user-ID bit is set
       -w FILE
              FILE exists and write permission is granted
       -x FILE
              FILE exists and execute (or search) permission is granted

參考資料：
Bash Shell: Check File Exists or Not

預設不啟動x window

為了節省資源，
在fedora可以預設把x window關掉。
打以下指令
# mv /etc/systemd/system/default.target /etc/systemd/system/default.target.bak
# ln -s /lib/systemd/system/runlevel2.target /etc/systemd/system/default.target

這樣下一次開機就不會啟動x window了

不過，若要啟動的話，
只要打
# startx
指令即可

參考資料：
Fedora 下设置系统不启动X window
Linux 的開機啟動流程

啟動ssh service

在fedora 20上啟動
# service sshd start

putty藍色字體看不清楚的問題

用putty連到linux server會出現藍色字體看不清楚的問題。

原本的顏色



選擇Colours的ANSI Blue，並且設定為以下數值
Red: 56
Green: 109
Blue: 199

這樣比較可以看的清楚了。



參考資料：
在putty 中设置字体的颜色和背景