linux 下 chrome 界面亂碼解決方法

修改 /etc/fonts/conf.d/49-sansserif.conf倒數第四行，改成下面這樣或是換成其他你喜歡的字型。


ubuntu


參考資料：
http://blog.csdn.net/loveaborn/article/details/29579787


如果上面這個方法無效，試試看下面指令
$ sudo apt-get install ttf-wqy-microhei ttf-wqy-zenhei xfonts-wqy

一些黑底白字的瀏覽器外掛或 pdf reader

chrome:

High Contrast

Night Reading Mode  (推薦）

pdf reader:

evince  (到 view -> inverted color 將白底換成黑底）

change java version in ubuntu

sudo update-alternatives --config java

How to build x86_64 image for qemu using buildroot

Download buildroot and change into buldroot folder. And then type below command.

make qemu_x86_64_defconfig
make -j8
qemu-system-x86_64 -M pc -kernel output/images/bzImage -drive file=output/images/rootfs.ext2 -append root=/dev/sda -vga std

Enjoy it.

scala 中 for ...yield 與 map, flatMap, withFilter 之互換

-------------------------------
for(x <- expr1) yield expr2
expr1.map(x => expr2)

-------------------------------

for(x <- expr1 if expr2) expr3
expr1.withFilter(x => expr2).map(x => expr3)

-------------------------------

for(x <- expr1 if expr2; seq) yield expr3
for(x <- expr1 withFilter expr2; seq) yield expr3

-------------------------------

for(x <- expr1; y <- expr2; seq) yield expr3
expr1.flatMap(x => for (y <- expr2; seq) yield expr3)

-------------------------------


for ((x1, x2) <- expr1) yield expr2
expr1.map{case(x1, x2) => expr2}

-------------------------------

for(pat <- expr1) yield2

expr1 withFilter {
  case pat = > true
  case _ => false
} map {
  case pat => expr2
}