Checksum is often used in Bitcoin when generating public key, address. Checksum is a simple method for error-checking data [1].
In Bitcoin blockchain the checksum is generated by running SHA256 function two times in a row.
Important note: need to use sha256 in binary mode for binary data.
This is an example used on learnmeabitcoin [1] and this bash analogue gives the same result:
Which program works faster? Does Rust compiler do things extra fast? Here are our simplest programs on Rust, C, C++, Bash, Python3. They were run 100.000 times and timings are measured.
Listing HelloWorld on Rust, main.rs
fn main() {
println!("Hello, World!");
}
Listing HelloWorld on C, main.c
#include <stdio.h>
int main() {
printf("Hello, World!\n");
return 0;
}
When update Drupal with composer on VPS with RAM less than 2Gb you may catch errors:
Sometimes my Devuan unexpectedly close the session, because of some JavaScripts on websites. After re-login I cannot connect to remote git repository with errors:
$ ssh remote_server
$ git pull
Error reading response length from authentication socket.
Permission denied (publickey).
fatal: The remote end hung up unexpectedly
Some people advise to start ssh-agent and load keys to ssh-agent, but that does not work in my case:
Tron Network has addresses that start with 'T' and have length 34 symbols. If you wish convenient address like TMYNAME93LRv...91F with 'MYNAME' string, so use my script on Python3.
Generates Tron Network addresses using tronpy library and writes addresses and private keys to log.txt
ProtonVPN allows to use Free VPN servers in Netherlands, USA, Japan. You may use official application for Linux, Android. But for fine configuring and connect just in one click need to connect with own script using OpenVPN configs by ProtonVPN. Here it is my own bash script for connect to the best protonvpn server in one click.
Intall tor, torsocks, openvpn, resolvconf, jq
apt-get install tor torsocks openvpn resolvconf jq
VPS have limited CPU and RAM usage. This is why it is hard to mine on VPS not being blocked for high consumption. I try to mine on Xeon Skylake 1 Core 2 Gb Ram.
Get config.json from Xmrig wizard [1]. After first run xmrig will add many lines to your config. And you need to look at the next lines.
Under randomx object: "mode": "light" - this makes xmrig uses 256 Mb of Ram.
Under randomx object: "1gb-pages": false - this is by default, use 2mb huge pages.
Raptoreum is a new blockchain where you can mine with official miner or also xmrig (from 6.16 release).
apt-get install curl build-essential libtool autotools-dev automake pkg-config python3 bsdmainutils cmake;
apt-get install python3-setuptools libcap-dev zlib1g-dev libbz2-dev
cd depends
make -j4
cd ..
./autogen.sh
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I use Protovpn and need to choose the fastest free server. All the servers are listed in json file: https://api.protonmail.ch/vpn/logicals Let's try linux jq. First install curl if you have no (apt-get install curl) and download json file: curl https://api.protonmail.ch/vpn/logicals > __tmp_protonvpn