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一台电脑绑定两个github账号

2017-12-10

git
在一台电脑上管理两个github账号，需要大家做以下步骤.

一、生成两个SSH Key

比如说，你有一个126的邮箱和一个gmail邮箱，名字分别取x和y.在.ssh/目录下使用下面的命令：
```
ssh-keygen -t rsa -C "[email protected]"

ssh-keygen -t rsa -C "[email protected]"
```
在键入第一条命令的时候，不要一路回车，需要你重命名一下，可以直接以id_rsa_x和id_rsa_y来命令，第二个提示框可以按回车直接进行下一步。这样就会生成四个文件:
```
id_rsa_x.pub      id_rsa_y.pub
id_rsa_x          id_rsa_y
```
上面以*.pub结尾的文件需要你填入你的两个github上面的设置的ssh key and gpg

单击上面的New ssh Key,把pub文件的内容填入对应的ssh的对应框。

二、添加私钥
1. 打开ssh-agent
```
ssh-agent -s
```
1. 添加私钥
```
ssh-add ~/.ssh/id_rsa_x

ssh-add ~/.ssh/id_rsa_y
```
三、创建config文件
```
	Host x.github.com
	hostName github.com
	PreferredAuthentications publickey

	IdentityFile ~/.ssh/id_rsa_x

	User x

Host y.github.com
HostName github.com
User y
IdentityFile ~/.ssh/id_rsa_y
```
四、远程测试
```
ssh -T x.github.com

ssh -T y.github.com
```
五、克隆并设置git的配置文件

将你的项目_clone_到本地，
```
git clone [email protected]:wahtever
```
还有一个重要的问题就是你的git配置文件大部分都设置为了全局文件，那么就要设置新的config文件，这是针对你的项目而言的。
```
# 取消全局　用户名/邮箱　配置,下面的user.name是你的原来的真实名字
git config --global --unset user.name
git config --global --unset user.email

#为每个repo设置不同的　用户名/邮箱
git config user.email "[email protected]"
git config user.name "x"
```
重建origin
```
git remote rm origin
git remote add origin [email protected]:whatever

# 重新push

git push origin master
```
Enjoy!
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git撤销已经push到远端的commit

2017-09-10

git
- question
- ways
question

If you have pushed commit into remote,how to reset it? Yes, from literly you know i means.

ways
```
git reset --soft <版本号>
```
Notes: --soft rollback verison before, but it retains the modifies for the local work, then restart push it.

--hard discards the modify.
```
git push origin <branch-name> --force
```
If you use the command without --force, it will reject.Forcing to over cover remote branch.

Done.
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wireshark使用入门

2017-08-03

network
快捷键

快捷键

The Menu

First, you have to understand it: in wireshark, the packet is very important concept.Above, items of menu have File,Edit, View, Go,Capture,Analyze and they use packets(born from TCP/IP) except file.

The main toolbar

The filter menu

The “packet List” pane

Each line in the packet list corresponds to one packet in the capture file, if you select a line in this pane, more details will be displayed in the “packet pane” and “Packet Bytes” panes.

The picture is very happy:

The “packet detailes “ pane

…

Starting Capture
```
wireshark -i eth0 -k
```
This will start Wireshark capturing on interface eth0.

Or you click “Capture” -> “Options”, which short key is ctrl + k. You can add it and linux command ifconfig into to test.

So, my eth0 is called ‘enp1s0’
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linux扩充swap容量

2017-08-03

kvms
This is a new post and it is sister message for http://www.aftermath.cn/kvms-resize.html

How to add Swap space

First, we can see if the filestsyem has any swap, you can type:
```
sudo swapon --show
```
If any thing does not display, this means your system does not have any swap space.

You can verify there is no active swap using free utility:
```
free -h
```
total used free shared buff/cache available Mem: 2.0G 105M 262M 11M 1.6G 1.7G Swap: 0B 0B 0B

Via df -h to check disk space

Create a swap file
```
sudo fallocate -l 2G /swapfile
```
The program fallocate to create a file named swapfile in our (/) directory.

Because we have a RAM is 1024MB, so we create a swapfile which space is 2G.
```
ls -hl /swapfile
```
You can verify it now.

Enable the swap file

Now, we do not turn this into swap space.Make the file only accessible to root by typing:
```
sudo chmod 600 /swapfile
```
Next, type:
```
sudo mkswap /swapfile
```
Then, to start utilizing it:
```
sudo swapon /swapfile
```
So, we have finished it.
```
sudo df -h

sudo free -h
```
Make swap permanent

Yes, it is in use on this start,you have to add it into /etc/fstab First, back up your /etc/fstab. Then,
```
echo '/swapfile none swap sw 0 0' | sudo tee -a /etc/fstab
```
Tweak your swap setting

The swappiness parameter configures how often your system swaps data out of RAM to the space. This is a value between 0 ans 100 that represents a percentage. If you have a deskop machine, the 60 is ok, but for server, it is better 0.
```
cat /proc/sys/vm/swappiness
```
It will show on my machine:
```
60
```
We can set the swappiness to a different value by using the sysctl command.
```
sudo sysctl.swappiness=10
```
If you want to it persent permenant , edit /etc/sysvtl.conf file to add:
```
vm.swappiness = 10
```
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虚拟机扩充容量

2017-08-02

kvms

一

一
二
步骤
At last

好不容易使用libvirt库结合qemu把虚拟机装起来，但是没有想到在跑项目的时候居然dik　space 太小了，看来是自己当初安装虚拟机的时候把容量给小了，想办法在整回去呗.

二

首先声明，我使用的是qemu自带的qcow2文件格式，但是好像这个并不会影响的使用。现在，我的kvms已经扩充完毕，有些数据已经拿不到了，但是思路还在的，我可以使用我的笔记再一次演示一遍的.

步骤

我的pool文件定义在/opt/kvms/pools/devel/debian-9.qcow2,

stop your VM
Use qemu-img resize /opt/kvms/pools/devel/debian-9.qcow2 +25G
Restart your VM
Adjust your VM LVM partition

First, the result below is updated,

 sudo fdisk -l
 Disk /dev/vda: 55 GiB, 59055800320 bytes, 115343360 sectors
 Units: sectors of 1 * 512 = 512 bytes
 Sector size (logical/physical): 512 bytes / 512 bytes
 I/O size (minimum/optimal): 512 bytes / 512 bytes
 Disklabel type: dos
 Disk identifier: 0x57a2ec91
Device     Boot Start       End   Sectors Size Id Type
/dev/vda1  *     2048 115343359 115341312  55G 83 Linux

But you must know, my /dev/vda1 is 10G size only,the 55G is result i resized it.

Next we use the fdisk tool to temporarily delete partition /dev/vda1,then create it bigger.

Here: section start 2048.

In fact, The fdisk have detected the space is 55G, but my /dev/vda1 is 10G only, because i dont’t resize the /dev/vda1 filesystem.

The process is:

# fdisk /dev/vda

Welcome to fdisk (util-linux 2.27.1).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Command (m for help): d
Selected partition 1
Partition 1 has been deleted.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-62914559, default 2048): 2048
Last sector, +sectors or +size{K,M,G,T,P} (2048-62914559, default 62914559): [ENTER for default]

Created a new partition 1 of type 'Linux' and of size 30 GiB.

Command (m for help): t
Selected partition 1
Partition type (type L to list all types): 83
Changed type of partition 'Linux' to 'Linux'.

Command (m for help): a
Selected partition 1
The bootable flag on partition 1 is enabled now.

Command (m for help): p
Disk /dev/vda: 30 GiB, 32212254720 bytes, 62914560 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x3ac5a058

Device     Boot Start      End  Sectors Size Id Type
/dev/vda1  *     2048 62914559 62912512  30G 83 Linux

Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Re-reading the partition table failed.: Device or resource busy

The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8).

First we enter d to delete a partition, As there is only one partition(/dev/vda1) it is automatically selected.
Next we create a new partioion

n to start the new partition function

p for a primary partition

1 to create /dev/vda1

2048 as our start sector

t is to set partition type, then enter 83 to set it to linux.
To set the bootable, press a for the boot function and enter 1 if prompted for the partition number.
Enter p to print the new partition table.
w is write to the partition table.

Ok, we have finished the partition　table.And you have noted the output, you have to use bash command to tell kerenl to load the new partition table.

partprobe /dev/vda

If success there is no output.

At last

The last step is very important for the process, because you donnot resize /dev/vda1 filesystem.We have expanded the partition but the filesystem has not been expanded to fill it. How? resize2fs

resize2fs /dev/vda1

Hope it works!

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leetcode题目总结

2017-07-01

leetcode
- Linked list
  - easy
刷了几道leetcode,感觉还是挺好的，现在整理一下题目，并归纳一下。

Linked list

easy
1. 逆置(reverse)单链表。题目解答
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57/90

Welcome to here

一台电脑绑定两个github账号

一、生成两个SSH Key

二、添加私钥

三、创建config文件

四、远程测试

五、克隆并设置git的配置文件

重建origin

git撤销已经push到远端的commit

question

ways

wireshark使用入门

快捷键

The Menu

The main toolbar

The filter menu

The “packet List” pane

The “packet detailes “ pane

Starting Capture

linux扩充swap容量

How to add Swap space

Create a swap file

Enable the swap file

Make swap permanent

Tweak your swap setting

虚拟机扩充容量

一

二

步骤

At last

leetcode题目总结

Linked list

easy