Introduction

I'm not an advanced console app ** I just happened to know CSI while I was making various things, so I wrote it.

What is CSI

A type of ** escape sequence **. The first thing that comes to mind when you hear the word "escape" is \ n. \ n is a very simple escape that means a newline in Unix, but this time we'll use a slightly more complicated special expression.

By the way, CSI is an acronym for * Control Sequence Introducer *.

What can i do

Typical ones --Move the cursor --Erase the screen (Erase everything before the cursor, delete everything after the cursor) --Clear line --Erase characters --Erase characters in rectangular units --Character style (bold, font color, background color, etc.) settings --Control of window information (size, etc.) etc…

** here ** has all the control types and methods.

About operation

~~ ** Bash doesn't seem to escape easily ** (reference). ~~ [Addition: Comment information] It seems that you can escape with Bash. Escapes are applied with the -e option, such as ʻecho -e`. Also, the above link was another discussion. We will correct.

Try using CSI

Now, in the previous example, we have shown \ n for line breaks. Since CSI can control multiple things, the control code is not one, but there is a prefix to recognize that it is CSI. That is ** \ e [** or ** \ 033 [** or ** \ 0x1b [**.

[Addition] I thought bash couldn't escape, just \ e [ didn't support it. It is possible with \ 033 [.

Since e is a character type, 033 is an octal number, and 0x1b is a hexadecimal number, it is essentially the same, but e is easier. CSI is a kind of [^ 1] escape sequence in the narrow sense. Inserting \ e at the beginning tells you the beginning of the escape sequence, and [ tells you that it is CSI.

CSI control changes depending on what you write after this.

CSI control list (partial)

Control characters (no spaces required)	motion
n A	n lines(1 line if not specified)Raise the cursor
n B	n lines(1 line if not specified)Lower the cursor
n C	n characters(1 character unless specified)Advance the cursor
n D	n characters(1 character unless specified)Move the cursor back
n E	Place the cursor on n lines(1 line if not specified)Align to the beginning below
n F	Place the cursor on n lines(1 line if not specified)Fit to the beginning of the top
n G	Place the cursor on the nth character of the current line(1st character if not specified)To match
n; m H	Place the cursor on the nth line, m character(1 character per line unless otherwise specified:upper left)To match
n J	Clear screen (details will be described later)
n K	Delete line (details will be described later)
n S	n lines (1 line if not specified) Scroll the screen to proceed
n T	n lines (1 line if not specified) Scroll back the screen
n L	Insert n lines (1 line if not specified) before the line where the cursor is
n M	Delete n lines (1 line if not specified) from the line where the cursor is
n P	Delete n characters (1 character if not specified) from the cursor position
n P	Replace n characters (1 character if not specified) with blanks from the cursor position
n `	Move the cursor to the nth character of the current line (1st character if not specified)
n a	Advance the cursor by n characters (1 character if not specified)
n d	Raises the cursor n lines at the current position (1 line if not specified)
n m	SGR(Select Graphic Rendition)Specify parameters (details will be described later)
s	Remember the current cursor position
u	Call the memorized cursor position
> 3; a; b; c; d J	(b, a)From(d, c)Erase rectangle up to
> 3; a; b; K	Erase characters a to b on the current line

Behavior of screen erase (* CSI * * n * J) and line erase (* CSI * * n * K)

n	behavior
Unspecified	Erase behind the cursor to the beginning of the screen (line)
0	Erase behind the cursor to the beginning of the screen (line)
1	Erase before the cursor to the end of the screen (line)
2	Erase the entire screen (line)

SGR parameters (typical)

n	meaning
None	Parameter reset
0	Parameter reset
1	Bold
2	Light print (not widely supported)
3	Italic (not widely supported, inverted)(n=7)Can also be)
4	Underline
5	Blinking: 150 times/Within minutes
6	Fast flashing: 150 times/More than a minute (not widely supported)
7	Reverse display: Foreground and background colors are swapped
8	Hide text (not widely supported)
9	Strikethrough (not widely supported)
10	Default font
11–19	(n-10)Use the second alternative font
20	Fraktur font(Mostlyunsupported)
21	Bold OFF (not widely supported),Double underline (almost unsupported)
22	Restore color and emphasis (bold / light)
23	Restore italics and fraktur
24	Cancel underline
25	Cancel blinking
28	Unhide text
29	Erase the strikethrough
30–37	Foreground color (essentially text color)(n-30)Change to number (color number will be described later)
38	Foreground color setting expansion.`\e[38;5;n`You can specify the color index with(0...255)。`\e[38;2;r;g;b`You can set RGB with(0 each...255)。
39	Reset foreground color
40–47	Background color(n-40)Change to number (color number will be described later)
48	Background scenery setting expansion.`\e[48;5;n`You can specify the color index with(0...255)。`\e[48;2;r;g;b`You can set RGB with(0 each...255)。
49	Reset background color

What's this unsupported storm ...

Color number

number	color
0	black
1	Red
2	Green
3	yellow
4	Blue
5	Magenta
6	cyan
7	White

It looks like this when you roughly display each color. スクリーンショット 2016-08-05 10.39.55.png

How to use SGR

When actually setting the SGR

echo "\e[31mred\e[m"

If you do, it will be displayed as red in red letters.

Also,

echo "\e[31;43mred&yellow\e[m"

If you do, it will display red & yellow with a red character yellow background. You can set multiple options at once by typing the options separated by ; in this way. ** Be sure to turn off the option at the end with \ e [m or \ e [0m "to avoid unexpected behavior after CSI exits. ** **

[^ 1]: Strictly speaking, \ n is not an escape sequence. In a narrow sense, it refers to a control byte string starting with ʻESC (0x1B)`.

[LINUX] "CSI" that I want to teach beginners in interactive console application production