ox0spy's blog

Jun 4, 2013

Run Android Java console program

$ cat Hello.java

class Hello {

public static void main(String[] args) {

System.out.println("Hello World!");

}

$ javac Hello.java

$ dx --version

dx version 1.7

$ dx --dex --output=Hello.dex Hello.class

$ ls

Hello.class Hello.dex Hello.java

$ adb push Hello.dex /data/local/tmp/

4.0 User版:

$ adb shell dalvikvm -cp /data/local/tmp/Hello.dex Hello

Dalvik VM unable to locate class 'Hello'

java.lang.NoClassDefFoundError: Hello

at dalvik.system.NativeStart.main(Native Method)

Caused by: java.lang.ClassNotFoundException: Hello

at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:61)

at java.lang.ClassLoader.loadClass(ClassLoader.java:501)

at java.lang.ClassLoader.loadClass(ClassLoader.java:461)

... 1 more

4.0 Eng版:

$ adb shell dalvikvm -cp /data/local/tmp/Hello.dex Hello

Hello World!

May 8, 2013

Linux Shell Basic Test

1. 目录下有a.txt,b.txt,c.txt 把他们改名为a.txt.bak,b.txt.bak,c.txt.bak
rename 's/$/.bak/' [a-c].txt

2. 在tmp目录下创建a0.txt,a1.txt,….a100.txt
for x in $(seq 0 100); do touch a${x}.txt;done

3. 递归删除/var/www目录下的所有“.svn”目录
find /var/www -type d -name '*.svc' -exec rm -rf {} \;

4. 查找并杀掉所有的nginx进程,进程名特征：“/usr/local/sbin/nginx”
ps aux | grep '/usr/local/sbin/nginx' | awk '{print $2}' | xargs kill

5. /var/log/wtmp文件过大了，需要清空这个文件，如何做？
# > /var/log/wtmp
$ sudo bash -c '> /var/log/wtmp'

6. shell中有哪些特殊字符，以及他们的含义和应用场合
file glob: ?, *, [x-y]
variable: $
quote: ', ", (), [], {}

7. 文件权限位的含义，如权限为601是什么意思?
rxw - 412
601 - rw-------x

8. bash下，命令行操作有哪些快捷键可以用？在哪里可以查到这些快捷键的说明？
bash -o vi
bash +o vi
vi, emacas

9. 如何定义函数，函数如何接受参数，返回值？
bash function define:
[function] func_name()
{
function body
}

args:
func_name args

$1, $2 ... ${n}

$*
$@

a)
global variable

b)
echo xxx

ret_val=$(func_name args)

c)
func_name variable_name

func_name()
{
local __var=$1
ret_val='test only'
eval $__var=$ret_val
}

Mar 4, 2012

3年过1天

转眼在成都三年过一天了，09年3月3号，30多小时火车从北京到成都，sz一直把我送上车。

3年后的同一天，sz也来到了成都，并打算在成都工作、生活了，一切源于去年十一他的成都几日游。

有好朋友过来，当然是很开心的事情，周末两天吃饭、找房，拿下一个套三的房子，离现在住的地方很近，现在这个套二基本也确定有人要租了，感觉很好。

这两天，带他看了些房子，他总会讲到华丽，北京的普通工薪族的生活看来比成都差太多。昨天去老码头吃火锅，我觉得一般，他们俩都感觉很好。

就胡言乱语到这吧，睡觉，明天早点回来搬家。

Sep 5, 2011

Install driver for Atheros AR9271 on Ubuntu

thinkpad x10 无线网卡太弱，买了块无线网卡，插入无法识别，打开带的光盘，里面只有windows驱动。

了解了下，已经有人做好了安装工具 - ath9k_htc-installer，还是deb包，下载安装，然后，终端运行

$ ath9k_htc-installer

出来一个图形界面，直接安装即可，然后，插入无线网卡，仍然无法识别
$ dmesg | tail
[ 143.882952] usb 1-1: ath9k_htc: Firmware - htc_9271.fw not found
[ 143.882983] ath9k_htc: probe of 1-1:1.0 failed with error -22

$ sudo wget -P /lib/firmware http://wireless.kernel.org/download/htc_fw/1.3/htc_9271.fw

重新插上，小灯开始闪烁了。

从 ath9k_htc-installer 的运行log看，这个工具应该是修改.config文件，然后重新编译kernel了，所以，和http://wireless.kernel.org/en/users/Drivers/ath9k_htc 讲的一样，只是不用一般用户自己编译kernel。

Jul 7, 2011

test

just test from my android phone!

Jun 29, 2011

lidroid 2.6 replace TouchWiz40Launcher to TouchWiz30Launcher

Samsung I9000, sometimes TWL4 is very slow, so I want to use TWL3.

download lidroid 2.7 from here.
$ unrar -e lidroid-sgs-2.7.0-i9000.rar
$ tar xvf PDA-i9000.tar.md5
$ sudo mount -o loop factoryfs.rfs /mnt
$ adb remout
$ adb push /mnt/app/TouchWiz30Launcher.apk /system/app
$ adb shell reboot

May 25, 2011

set time zone on Ubuntu

Modify time zone on Ubuntu 10.04.

$ sudo tzselect

$ sudo ln -sf /usr/share/zoneinfo/Asia/Shanghai /etc/localtime

$ sudo ntpdate cn.pool.ntp.org

# disable UTC
$ sudo sed -i 's/^UTC=yes/UTC=no/' /etc/rcS

setup vpn server on Amazon EC2

My environment: Amazon free EC2, Ubuntu 10.04 64bit

You should modify some hard code.

server side

$ cat setup-pptpd.sh

#!/bin/bash

# install pptpd
apt-get install -y pptpd

# config pptpd
echo "localip 192.168.2.1" >> /etc/pptpd.conf
echo "remoteip 192.168.2.2-10" >> /etc/pptpd.conf
echo "ms-dns 172.16.0.23" >> /etc/ppp/options.pptpd
echo "ms-dns 8.8.8.8" >> /etc/ppp/options.pptpd

# generate user's password
passwd=`openssl rand 10 -base64`
if [ "$1" != "" ]
then passwd=$1
fi

# setup authenticated user
echo "user pptpd $passwd *" >> /etc/ppp/chap-secrets

# for ipv4 forwarding
sed -i 's/^#net.ipv4.ip_forward = 1/net.ipv4.ip_forward = 1/' \
 /etc/sysctl.conf
sysctl -p

# use iptabes to get the net forward
iptables -t nat -A POSTROUTING -s 192.168.2.0/24 -j SNAT \
 --to-source $(ifconfig  | grep 'inet addr:'| \
 grep -v '127.0.0.1' | cut -d: -f2 \
 | awk 'NR==1 { print $1}')
iptables -A FORWARD -p tcp --syn -s 192.168.2.0/24 \
 -j TCPMSS --set-mss 1356
service iptables save

# make the iptables and pptpd auto start
chkconfig iptables on
chkconfig pptpd on

service iptables start
service pptpd start

echo "VPN service is installed"
echo "VPN username is user,VPN password is $passwd"

client side

$ cat setup-pptp-client.sh

#!/bin/bash

apt-get install -y pptp-linux

# modify those variable for your environment
vpn_server="1.2.3.4"
user="user"
passwd="secret"

echo "pty \"pptp $vpn_server --nolaunchpppd\"
name $user
remotename pptpd 
require-mppe-128
file /etc/ppp/options.pptp
ipparam pptpd" > /etc/ppp/peers/pptpd

echo "$user pptpd $passwd *" >> /etc/ppp/chap-secrets

echo "setup vpn client done."
echo -e "now, you shoule run:"
echo -e "\t$ pon pptpd # start pptpd"

echo -e "\t$ pon pptpd debug dump logfd 2 nodetach # debugging"
echo -e "\t$ poff pptpd # stop pptpd"
echo -e "\t$ ifconfig # check network config"

May 20, 2011

awk after the number of field or the value of field changed

# from awk manpage
References to non-existent fields (i.e. fields after $NF) produce the null-string.
However, assigning to a non-exis‐tent field (e.g., $(NF+2) = 5) increases the value of NF,
creates any intervening fields with the null string as their value, and causes the value
of $0 to be recomputed, with the fields being separated by the value of OFS.

References to negative numbered fields cause a fatal error.

Decrementing NF causes the values of fields past the new value to be lost,
and the value of $0 to be recomputed, with the fields being separated by the value of OFS.

Assigning a value to an existing field causes the whole record to be rebuilt when $0 is referenced.
Similarly, assigning a value to $0 causes the record to be resplit, creating new values for the fields.

意思是:
1. 引用不存在的字段，会使增加NF的值，$0要根据OFS的值重新创建，中间的字段设置为空字符串, 然后根据FS的值重新对$0进行分割.
如:
$ echo 'a b c' | awk '{print $0; $6=60; OFS=":"; print $0}'
a b c
a:b:c:::60
可以清楚的看到, 第4,5字段的值都是空字符串.

2. 引用编号小于零的字段，会引起错误.
如:
$ cal | awk '{print $-1}'
awk: (FILENAME=- FNR=1) fatal: attempt to access field -1

3. 减少NF的值，编号大于NF的字段将丢失，$0根据OFS的值重新创建，然后根据FS的值重新分割记录.
如:
$ echo 'a b c d e f' | awk '{print $0; NF=3; print $0}'
a b c d e f
a b c

4. 给存在的字段赋值，使$0根据OFS的值重新创建，然后根据FS的值重新分割记录.
如:
$ echo 'a b c' | awk '{print $0; $1=$1;OFS=":"; FS=":"; print $0; print $1}'
a b c
a:b:c
a

5. 给$0赋值，$0现在是被赋予的新值，$0根据FS的值重新分割记录.
$ echo 'a b c' | awk '{print $0; $0=$0;OFS=":"; FS=":"; print $0; print $1}'
a b c
a b c
a

echo 'a b c' | awk '{print $0; $0="c d e"; print $0; print $1}'
a b c
c d e
c

note:
a. 4, 5是ChinaUnix.net Shell 编程大赛的第8题.
b. 可以发现当字段个数或者字段被修改后，都要根据OFS的值进行$0重建, 然后，$0根据FS的值重新分割.
c. 只修改$0, 使$0用新值根据FS的值重新分割.

May 9, 2011

build Android 2.3, ld cannot find -lz

Build Android 2.3 (gingerbread), report error: /usr/bin/ld: skipping incompatible /usr/lib/libz.so when searching for -lz /usr/bin/ld: skipping incompatible /usr/lib/libz.a when searching for -lz /usr/bin/ld: cannot find -lz collect2: ld returned 1 exit status fix it: $ sudo apt-get install lib32z-dev

Apr 7, 2011

GNOME 3.0 released

http://www.gnome.org/press/2011/04/gnome-3-0-released-better-for-users-developers-3/
http://linuxtoy.org/archives/gnome3.html

Mar 25, 2011

c tips from wang

wlh走前给大家分享的一些c tips，我还没搞懂，先记下

#include <stdio.h>

#define get_parent(x) (struct A*)((unsigned int)x - (unsigned int)&((((struct A*)0)->j)))

struct A
{
    char name[37];
    int i;
    int j;
    int k;
    char city[37];
};

void func(int* p_int)
{
    printf("in function %x\n", (unsigned int)get_parent(p_int));
}

int main()
{
    struct A a_var;
    printf("address of a_var is %x\n", (unsigned int)&a_var);
    func(&(a_var.j));
    return 0;
}

变态的面试题

从下面两个地方看到的 via Google Reader ...
http://www.kernelchina.org/?q=node/961
http://coolshell.cn/articles/3961.html

int n=20;
for(int i=0; i<n; i--){
    printf("-");
}

将上面的代码，修改或添加一个字符，使程序可以输出20个减号.（据说c有三种；java有二种修改方法）
C代码:

#include <stdio.h>

int main(int argc, char *argv[])
{
    /* first way */
    int n=20;
    for(int i=0; i<n; n--){
        printf("-");
    }
    printf("\n");

    /* second way */
    n=20;
    for(int i=0; -i<n; i--){
        printf("-");
    }
    printf("\n");

    /* third way */
    n=20;
    for(int i=0; i+n; i--){
        printf("-");
    }
    printf("\n");

    return 0;
}

Java代码:

class Test
{
    public static void main(String[] args)
    {
        /*
        int n=20;
        for(int i=0; i<n; i--){
            printf("-");
        }
        */

        /* first way */
        int n=20;
        for(int i=0; i<n; n--){
            System.out.print("-");
        }
        System.out.print("\n");

        /* second way */
        n=20;
        for(int i=0; -i<n; i--){
            System.out.print("-");
        }
        System.out.print("\n");
    }
}

C中的第三种：

/* third way */
n=20;
for(int i=0; i+n; i--){
    System.out.print("-");
}
System.out.print("\n");

$ javac Test.java
Test.java:28: incompatible types
found   : int
required: boolean
        for(int i=0; i+n; i--){
                      ^
1 error

Mar 23, 2011

enable core dump on Debian

globally enable core dump on Debian
1. edit /etc/security/limits.conf, add the bellowing line

*               soft    core            unlimited

2. logout and login

$ ulimit -c
$ ulimit -a

blogspot code syntax highlight

以前写的blogspot贴代码:http://ox0spy.blogspot.com/2009/03/test.html
参考: http://mlawire.blogspot.com/2009/07/blogger-syntax-highlighting.html
下载模板，在 </head> 前添加

    <!-- highlighting code -->
    <link href='http://alexgorbatchev.com/pub/sh/current/styles/shCore.css' rel='stylesheet' type='text/css'/>
    <link href='http://alexgorbatchev.com/pub/sh/current/styles/shThemeDefault.css' rel='stylesheet' type='text/css'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shCore.js' type='text/javascript'/>
    <!-- add brushes here -->
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushJScript.js' type='text/javascript'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushBash.js' type='text/javascript'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushSql.js' type='text/javascript'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushXml.js' type='text/javascript'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushCpp.js' type='text/javascript'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushPython.js' type='text/javascript'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushPerl.js' type='text/javascript'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushJava.js' type='text/javascript'/>
    <script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushPlain.js' type='text/javascript'/>
    <script type='text/javascript'>
      SyntaxHighlighter.config.bloggerMode = true;
      SyntaxHighlighter.all();
    </script>

然后上传模板，保存 ...
测试c程序

#include <stdio.h>

int main(int argc, char* argv[])
{
    printf("test only ...\n");
    return 0;
}

测试bash程序

#/bin/bash

echo "test only ..."

不希望显示行号，使用: class="brush:bash; gutter:false"

Mar 22, 2011

一道笔试题

#include <stdio.h>
#include <string.h>

char *shift_r(const char *src, const int n, char *dst)
{
    int i, len;

    if (src == NULL || (len = strlen(src)) == 0)
        return (dst = NULL);

    for (i = 0; i < len; i++)
        dst[(i+n)%len] = src[i];
    dst[i] = '\0';

    return dst;
}

int main(int argc, char *argv[])
{
    const char *src = "abcdef";
    char dst[80];
    const int n = 2;

    printf("%s\n%s\n", src, shift_r(src, n, dst));

    return 0;
}

好吧，这个也算 ... 口头描述这个真没劲 ...

#!/bin/bash

echo "testing for ..."
for ((i=0; i < 10; i++))
do
    echo $i
done

echo "testing while ..."
i=0
while [ $i -lt 10 ]
do
    echo $i
    i=$((i+1))
done

Mar 18, 2011

学习 qt c++

下次需要学什么还是碰到就开始好好学，过去这么多时间，悲剧阿 ...

log ...

Mar 15, 2011

Installing Debian from USB

download files

vmlinuz
initrd.gz
debian-6.0.0-i386-netinst.iso

syslinux.cfg

    label linux
    kernel vmlinuz
    append initrd=initrd.gz ramdisk_size=12000 root=/dev/rd/0 init=/linuxrc rw

    default linux
    prompt 1
    timeout 0

Make bootable USB

Note: in this example, the USB stick is SCSI device /dev/sdb
$ sudo apt-get install mtools syslinux dosfstools
$ sudo modprobe usb-storage
$ sudo fdisk -l /dev/sdb
$ sudo mkdosfs -I /dev/sdb
$ sudo syslinux /dev/sdb
$ sudo mount /dev/sdb /mnt
$ sudo cp -f vmlinuz initrd.gz syslinux.cfg debian-6.0.0-i386-netinst.iso /mnt
$ sudo umount /mnt

boot from USB stick

set the first boot device in the BIOS to USB-ZIP.
insert your USB drive, and boot your computer.

Mar 10, 2011

同事的你 [zz]

* author: unknown, 来自网络

* description: 这个时间看到这个歌词，感慨万千 ~

明天你是否会想起

昨天你写的程序

明天你是否还惦记

曾经爱编程的你

领导们都已想不起

曾经加班的你

我也是偶然看程序

才想起同事的你

谁聘了牛B烘烘的你

谁安慰天天加班的你

谁把你的设计做起

谁给你做的升级

你从前总是很小心

从不把离职的事提起

你也曾无意中说起

薪水实在太低

那时候屏幕总是在闪

日子总过得太慢

你总说离职遥遥无期

转眼就各奔东西

谁聘了牛B烘烘的你

谁安慰天天加班的你

谁看了我给你写的信

谁把它删在垃圾文件夹里

从前的日子都远去

我也将有我的新上司

我也会给他编程序

给他讲同事的你

谁聘了牛B烘烘的你

谁安慰天天加班的你

谁把你的设计做起

谁给你做的升级

. . .

Mar 3, 2011

Python Challenge

http://www.pythonchallenge.com

太有意思了，已经使我无法认真看 Android App 开发了 ...
我把自己做得答案都放到 github 上了,
https://github.com/ox0spy/Python-Challenge

Pages

Jun 4, 2013

May 8, 2013

Mar 4, 2012

Sep 5, 2011

Jul 7, 2011

Jun 29, 2011

May 25, 2011

server side

client side

May 20, 2011

May 9, 2011

Apr 7, 2011

Mar 25, 2011

Mar 23, 2011

Mar 22, 2011

Mar 18, 2011

Mar 15, 2011

download files

Make bootable USB

boot from USB stick

Mar 10, 2011

Mar 3, 2011