Simple Ethereum

1. bitcoin is BTC and eth is Ethereum
the concept of bitcoin was first proposed by Nakamoto on November 1, 2008, and was officially born on January 3, 2009 [1]. According to the idea of Nakamoto, the open source software is designed and released, and the P2P network on it is constructed. Bitcoin is a virtual encrypted digital currency in the form of P2P. Point to point transmission means a decentralized payment system
Ethereum is an open source public blockchain platform with smart contract function, which provides decentralized Ethereum virtual machine to process point-to-point contract through its special cryptocurrency ether (ETH)

warm tips:
1. The above information is for reference only, without any suggestions
2. According to the notice on preventing the financing risk of token issuance, there is no approved digital currency trading platform in China. According to the regulation of digital currency in China, investors have the freedom to participate in digital currency transactions at their own risk
response time: February 1, 2021. Please refer to the official website of Ping An Bank for the latest business changes
[Ping An Bank I know] want to know more? Come and see "Ping An Bank I know" ~
https://b.pingan.com.cn/paim/iknow/index.html

2. My computer - & gt; Attribute - & gt; Advanced - & gt; Environment variables - & gt; Add the following environment variables to the system variables:
java_ The home value is: the directory where JDK is installed, and mine is C: &# 92; Program Files\ Java\ jdk1.6.0_ 34
the classpath value is:;% JAVA_ HOME%\ lib\ tools.jar;% JAVA_ HOME%\ lib\ dt.jar;% JAVA_ HOME%\ bin;( Pay attention to the & quot& quot; To add)
Path: append at the beginning.;% JAVA_ HOME%\ bin;% JAVA_ HOME%\ jre\ bin;( Pay attention to the & quot& quot; To add)

after the installation, you can check whether the JDK is installed successfully. Open the CMD window and enter Java – version to view the version information of JDK.

3. Hello, from my point of view, it should be B, because a bought a good proct, but B gave it substandard, so the resulting losses should be borne by B.
this may be found from the contract law and the losses caused by violation,

4. A: 1. The most common methods of cost accounting in commercial enterprises are purchase price method and selling price method
2. Purchase price accounting, also known as "purchase price bookkeeping, inventory and sales", is an accounting method that controls the purchase, sales and inventory of goods by the person in charge of the physical object (or counter group) based on the total amount of purchase price. Its accounting features are: after the purchase of goods, register the sub ledger of goods in stock set by the person in charge of the goods, only recording the amount of purchase price, not the quantity; After commodity sales, credit the "commodity sales revenue" account according to the actual sales revenue, do not carry forward the cost of commodity sales at ordinary times, conct regular physical inventory, find out the actual quantity, and calculate and carry forward the cost of commodity sales with the final purchase price method. This method is suitable for selling bulk commodities with large unit value. The disadvantage is that it's troublesome
3. Supermarkets and department stores usually use the "selling price method" to calculate the cost of goods. Price accounting method is suitable for retail businesses with complicated commodities, but the premise is that the price is uniform (indivial price changes also need to go through relevant proceres), the cost of sales is carried forward according to the price in each period, the price difference rate between purchase and sale is calculated at the end of the month, and then the price difference between purchase and sale of the sold commodities is obtained, and then the cost is adjusted. This accounting method is not applicable in today's market economy.

5. Do you buy routers and firewalls without service
the connection depends on the configuration, not the port. Ge0 means Gigabit port 0, eth0 is Ethernet port 0
find a router seller to help you configure it.

6. 1. Print the current working directory -------- PWD
2. Display the contents of the current directory in a long list -------- LS - L
3. Display the contents of / etc / passwd file in pagination, ----------------Cat / etc / passwd | more
4. Modify your password -------- --- passwd (your user name)
5. Return your home directory from anywhere -------- Cd ~ (or CD enter directly)
6. Display your IP address and other configuration information -------- ifconfig
7. Test to gateway 172.23.196.1 Connect or not -------- Ping 172.23.196.1

LS – La -------- display the current directory file (A: display all files). l: List display)
CD.. --- - enter the previous directory (same as "up" of windows)
DF -------- display the usage of each partition
ifconfig -------- view the network card configuration
PWD -------- display the current directory
MKDIR -------- create directory
cat -------- display the file content
cat / etc / passwd | more ------ displays the contents of the / etc / passwd file in pagination mode (I copied your file directly, ha ha)
less ------ can view up and down (compared with more)
more ------ displays the file in pagination mode. Only down
Pico -------- one editor
Ping 172.23.196.1 -------- I won't explain this.
ifup eth0 -------- activate eth0
ifdown eth0 -------- corresponds to the above. Close eth0
who & gt; Week4-wholist.txt -------- who queries the current online users. The latter part means that the query results are saved in the file week4-wholist.txt
Chmod 755 index.html -------- change index. Htm property is 755 (don't say you don't know what 755 means)
sudo VI / etc / passwd -------- edit passwd with VI as root (it seems that you can't edit this file without root.)
MKDIR, CD, cat, Pico, PS, Cal, write, etc. --- too many. I don't want to explain. Tired
telent ubuntu.unix-center.net ------- use telne to connect to the following server
FTP 172.23.196.126 -------- log in to FTP server. 172.23.196.126

7. The environment is very simple:
a Linux (RedHat AS3) machine (kernel 2.4.21)
public network eth0
private network eth1
in the past, the private network was connected to 192.168.10 network segment with VLAN ID of 10
now I want to add 192.168.240 network segment while retaining the original 10 network segments, VLAN ID is 240
in fact, the answer to this question is very simple
that is to use vconfig
vconfig add eth1 10
vconfig add eth1 240
then ifconfig eth1.10 with IP, ifconfig eth1.240 with IP address, with vconfig we should be able to almost solve this problem
of course, on the switch, you have to configure this port to trunk mode, not only in the network segment with VLAN ID 10, but also in the network segment with VLAN ID 240
what I'm talking about here is how to "configure". That is to say, there is no need to write a startup script or change the original startup process. That is to say, after the machine is restarted (or / etc / RC. D / init. D / network restart), the network devices of the system will be OK, which can pass through 192.168.10 and 192.168.240
I carefully looked at the script file of the startup process, The discovery is very simple:
1. Edit the file / etc / sysconfig / network
add a line:
VLAN = yes
2. Generate the configuration files ifcfg-eth1.10 and ifcfg-eth1.240
CD / etc / sysconfig / network scripts
CP ifcfg-eth1 ifcfg-eth1.10
CP ifcfg-eth1 ifcfg-eth1.240
3. Edit the files ifcfg-eth1.10 and ifcfg-eth1.240
3 It is similar to the syntax of writing ifcfg-eth1 with the IP address, netmask, network, etc. of the 192.168.10 and 192.168.240 network segments of the server
note: the device of these two files should be changed to eth1.10 and eth1.240 respectively (these two files are copied from ifcfg-eth1, so they should be eth1)
4. Edit ifcfg-eth1
VI ifcfg-eth1
delete ippaddress, ifcfg-eth1, ifcfg-eth1, etc Netmask and network, which are related to IP address,
everything is OK. Whether it's / etc / rc.d/init.d/network restart or reboot, the system you'll get will connect to 192.168.10 and 192.168.240
tested on RedHat enterprise advance server 3, and no problem on RedHat 9.

8. My children are so good