How to use curl

What's curl?
A simple CUI http client.

Basic syntax

curl <options> <url>

Other options

Moved to Gist 

https://gist.github.com/cocoa-maemae/ea33cd5bf4d170b9c63d365e79b212a5

Linux environment variables

$PATH
the path referred by shell

$SHELL
shell name

$USER
login name

$PWD
current directory

$HOSTNAME, $HOST
machine host name

$TERM
terminal name

$MACHTYPE
machine name

$PS1
prompt display format

How to use nkf

What's nkf?
The tool to estimate a character code or to exchange a character code.

Basic syntax

nkf <options> <file name>

options

Movet to Gist.

https://gist.github.com/cocoa-maemae/f3c4a60907b9e1527435d99fb664cc91

The difference of .bash_profile, .bashrc

Brief

Detail about .bash_profile and .bashrc on CentOS


The differences of .bashrc and .bash_profile

When login to Linux, both $HOME/.bash_profile and $HOME/.bashrc are executed.

When a shell is run, an only .bahsrc is executed.

So if you want to run only when login, write the process to $HOME/.bash_profile
If you want to run every time bash is run, write the process to $HOME/.bashrc

Memory segment

Brief
Summarize memory segment

Basic memory segment
Nevertheless any languages, basic memory segment is like the below.

The roles of respective segments are like the below.

Stack segment
Contains stack. Stack is basically used for function calling. Nested functions are put in stack.

Heap segment
Contains heap. Heap is used for dynamic data which is not put in stack.

BSS segment
Contains uninitialized variables including static.
e.g.
int a;
static int a;

Data segment
Contains variables which have a pre-defined variables.
e.g.
int a = 8;
static int a = 8;
char String[] = "hoge";

Text segment
Contains mechanical languages. Data in this segment is always read only.

How to refurbish tmux

Brief
Surmise how to refurbish tmux

Requirements
OS: CentOS, Ubuntu

How to refurbish

Create $HOME/.tmux.conf

The blow is a sample of .tmux.conf
https://gist.github.com/cocoa-maemae/5e00a4d696d69e7b410d133714771d5d


Debug

If $HOME/.tmux.conf is not reflected, kill a tmux process then run tmux again.

e.g.

# Look into a tmux process

ps aux | grep tmux

25718 ? Ss 1:37 tmux
18937 pts/8 S+ 0:00 grep tmux

# kill a tmux process

kill -9 25718

How to use tmux

What is tmux?
Multiple virtual console tools

How to install

(CentOS)
sudo yum install -y tmux
Basic Usage
# Create windows
Ctrl-b,c

# Move to a next window
Ctrl-b,n

# Move to a previous window
Ctrl-b,p

# Divide a pane
Ctrl-b,%

# Move a pane
Ctrl-b,o