cp -r ${dir_name}

The cp command on Unix/linux is a command to copy files and directories. Since the cp command has existed for a long time(it appeared in the first Unix V1), it can be used with any UNIX/Linux OS.

option
-R : copy directory recursively

[vagrant@localhost tests]$ ls
index.php test
[vagrant@localhost tests]$ cp -r test test2
[vagrant@localhost tests]$ ls
index.php test test2

すげーーーーーー

ssh -i /path/to/key

It uses ssh(secure shell) protocol(encrypt communication between client and remote machine), so you can safely execute command. In addition, since the ssh command can use key authentication using secret key / public key, you can further improve security by using them.

ssh -i /path/to/key

Specify the private key file(identity file). In the initial setting, SSH version 1 is /.ssh/identity, ssh version 2 is /.ssh/id_rsa and /.ssh/id_dsa

Install the Truffle framework

We will use the Truffle framework to issue tokens. Truffle is Ethereum’s Smart Contract Development Framework, which has functions such as compiling, linking, deploying, and binary management.

[vagrant@localhost crypto]$ npm -v
1.3.6

First of all, we will install Truffle.

[vagrant@localhost crypto]$ npm install -g truffle
npm http GET https://registry.npmjs.org/truffle
npm http GET https://registry.npmjs.org/truffle
npm http GET https://registry.npmjs.org/truffle
npm ERR! Error: CERT_UNTRUSTED
npm ERR!     at SecurePair. (tls.js:1430:32)
npm ERR!     at SecurePair.emit (events.js:92:17)
npm ERR!     at SecurePair.maybeInitFinished (tls.js:1029:10)
npm ERR!     at CleartextStream.read [as _read] (tls.js:521:13)
npm ERR!     at CleartextStream.Readable.read (_stream_readable.js:341:10)
npm ERR!     at EncryptedStream.write [as _write] (tls.js:418:25)
npm ERR!     at doWrite (_stream_writable.js:226:10)
npm ERR!     at writeOrBuffer (_stream_writable.js:216:5)
npm ERR!     at EncryptedStream.Writable.write (_stream_writable.js:183:11)
npm ERR!     at write (_stream_readable.js:602:24)
npm ERR! If you need help, you may report this log at:
npm ERR!     
npm ERR! or email it to:
npm ERR!     

npm ERR! System Linux 2.6.32-754.3.5.el6.x86_64
npm ERR! command "node" "/usr/bin/npm" "install" "-g" "truffle"
npm ERR! cwd /home/vagrant/local/crypto
npm ERR! node -v v0.10.48
npm ERR! npm -v 1.3.6
npm ERR!
npm ERR! Additional logging details can be found in:
npm ERR!     /home/vagrant/local/crypto/npm-debug.log
npm ERR! not ok code 0

what!?

Issue ERC 20 token

ERC 20 token is a standard for issuing tokens with Ethereum, and by issuing a token conforming to ERC20, simplification of exchange between different tokens has been realized. In addition, we can manage tokens collectively by utilizing ERC 20 compatible wallet. ERC stands for Ethereum RFC and ERC 20 stands for the 20th specification. Representative ERC 20 tokens include 0x, Augur, OmiseGo and others.

Requirements for creating ERC 20 tokens are defined, and seems to be able to issue tokens by implementing the following six methods and two events.

fucntion totalSupply() constant returns(unit totalSupply);

function balanceOf(address _owner) constant returns (unit balance);

function transfer(address _to, unit _value) returns (bool success);

function transferFrom(address _from, addess _to, unit _value) returns (bool success);

function approve(address _spender, unit _value) returns(bool success);

function allowance(address _owner, address _spender) constant returns (unit remaining);

event Transfer(address indexed _from, address indexed _to, unit _value);

event Approval(address indexed _owner, address indexed _spender, unit _value);

vagrant : default paused (virtualbox)

I never seen 404 like below.

>vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Checking if box 'bento/centos-6.8' is up to date...
==> default: There was a problem while downloading the metadata for your box
==> default: to check for updates. This is not an error, since it is usually due
==> default: to temporary network problems. This is just a warning. The problem
==> default: encountered was:
==> default:
==> default: The requested URL returned error: 404
==> default:
==> default: If you want to check for box updates, verify your network connection
==> default: is valid and try again.
==> default: Unpausing the VM...

what does it mean?

>vagrant status
Current machine states:

default                   paused (virtualbox)

The VM is paused. This VM may have been paused via the VirtualBox
GUI or the VBoxManage command line interface. To unpause, please
use the VirtualBox GUI and/or VBoxManage command line interface so
that vagrant would be able to control the VM again.

once again, put “vagrant up” on the command line.

>vagrant up
Bringing machine 'default' up with 'virtualbox' provider...
==> default: Checking if box 'bento/centos-6.8' is up to date...
==> default: There was a problem while downloading the metadata for your box
==> default: to check for updates. This is not an error, since it is usually due
==> default: to temporary network problems. This is just a warning. The problem
==> default: encountered was:
==> default:
==> default: The requested URL returned error: 404
==> default:
==> default: If you want to check for box updates, verify your network connection
==> default: is valid and try again.
==> default: Machine already provisioned. Run `vagrant provision` or use the `--provision`
==> default: flag to force provisioning. Provisioners marked to run always will still run.

That says “vagrant provision”. Try again, boy.

>vagrant provision

>vagrant status
Current machine states:

default                   running (virtualbox)

The VM is running. To stop this VM, you can run `vagrant halt` to
shut it down forcefully, or you can run `vagrant suspend` to simply
suspend the virtual machine. In either case, to restart it again,
simply run `vagrant up`.

What!? I know, I’m just playing.

vagrant has multiple choices for machine provisioning, from simple shell scripts to more complicated industry standard configuration management systems.

I you have never used a configuration management system in the past, starting with basic shell scripts for provisioning is recommended.

git diff

First of all, as a basic concept of git diff, the basic behavior of “git diff” is “display of changes made in the working tree”.

Then, if you do not specify the comparison source, you can specify “comparison source” as an argument, but by default, the difference when compared with “index” →　”working tree” with “index” as the comparison source and it will display.

[vagrant@localhost tests]$ git diff
diff –git a/sample.txt b/sample.txt
deleted file mode 100644
index 106287c..0000000
— a/sample.txt
+++ /dev/null
@@ -1 +0,0 @@
-Hello Git!
diff –git a/tests/test b/tests/test
— a/tests/test
+++ b/tests/test
@@ -1 +1 @@
-Subproject commit 180cf3fcce48d905ede71a57ed0bd3973e1f90c8
+Subproject commit 180cf3fcce48d905ede71a57ed0bd3973e1f90c8-dirty
[vagrant@localhost tests]$ git diff –name-only
sample.txt
tests/test

あれ？

[vagrant@localhost test]$ git diff –name-only
addfile.txt
[vagrant@localhost test]$

OK、理解した。

HDML??

Markup language for creating content for mobile information terminal. It is used in EZweb which can be used with au’s mobile phone. One page is handled as “card” and a group of multiple cards is called “deck”. Data is transmitted and received on a deck basis. It is not compatible with Compact HTML which is a description language for the same portable information terminal.

What is an escape sequence (escape character)?

An escape sequence is a special character string that controls character output, such as character color change, cursor movement, and character deletion, when outputting characters on the screen, rather than outputting the characters themselves.

In addition to the information that people can recognize as “character”, information other than “characters” such as control characters and character editing information on the OS is also included a s character information used in the OS. These characters are sometimes called “special characters”. An escape sequence exists for this special character to let people enter characters and tell it to the OS.

Typical escape sequences include the following characters.

\a : bell character(alert)
\b : return one character
\f : page feed(clear)
\n : line feed, return
\r : back to the beginning of the same line
\t : horizontal tab
\v : vertical tab
\\ : show \
\' : single quotation mark
\" : double quotation mark
\0 : null

Linux $ source

“source” is a command to execute the command described in the file.

list.txt

echo Hello

[vagrant@localhost tests]$ ls
index.php list.txt test.php tinymce
[vagrant@localhost tests]$ source list.txt
Hello

wow.

isExist APP ~ "pgrep httpd"
if [[ -n $isExist App ]]i then
	 service httpd stop
fi

あああああああああ、シェルスクリプト勉強しなきゃ。。。駄目だ、時間がかかりすぎる。

tail -n 100 /var/log/httpd/error_log | egrep -i “WARN|ERR|FAIL|CRIT”

Can use the tail command to export the file specified in the File parameter from the specified position to standard output.

[vagrant@localhost ~]$ tail -n 100 /var/log/httpd/error_log
[Sun Feb 10 09:48:03 2019] [notice] Digest: generating secret for digest authentication …
[Sun Feb 10 09:48:03 2019] [notice] Digest: done
[Sun Feb 10 09:48:03 2019] [notice] Apache/2.2.15 (Unix) DAV/2 configured — resuming normal operations