mirror of
https://github.com/flokoe/bash-hackers-wiki.git
synced 2024-11-01 14:53:06 +01:00
364 lines
13 KiB
Markdown
364 lines
13 KiB
Markdown
---
|
|
tags:
|
|
- bash
|
|
- shell
|
|
- scripting
|
|
- colors
|
|
- cursor
|
|
- control
|
|
- vt100
|
|
- ansi
|
|
---
|
|
|
|
# Terminal codes (ANSI/VT100) introduction
|
|
|
|
Terminal (control) codes are used to issue specific commands to your
|
|
terminal. This can be related to switching colors or positioning the
|
|
cursor, i.e. anything that can't be done by the application itself.
|
|
|
|
## How it technically works
|
|
|
|
A terminal control code is a special sequence of characters that is
|
|
printed (like any other text). If the terminal understands the code, it
|
|
won't display the character-sequence, but will perform some action. You
|
|
can print the codes with a simple `echo` command.
|
|
|
|
<u>**Note:**</u> I see codes referenced as "Bash colors"
|
|
sometimes (several "Bash tutorials" etc...): That's a completely
|
|
incorrect definition.
|
|
|
|
## The tput command
|
|
|
|
Because there's a large number of different terminal control languages,
|
|
usually a system has an intermediate communication layer. The real codes
|
|
are looked up in a database **for the currently detected terminal type**
|
|
and you give standardized requests to an API or (from the shell) to a
|
|
command.
|
|
|
|
One of these commands is `tput`. Tput accepts a set of acronyms called
|
|
*capability names* and any parameters, if appropriate, then looks up the
|
|
correct escape sequences for the detected terminal in the `terminfo`
|
|
database and prints the correct codes (the terminal hopefully
|
|
understands).
|
|
|
|
## The codes
|
|
|
|
In this list I'll focus on ANSI/VT100 control codes for the most common
|
|
actions - take it as quick reference. The documentation of your terminal
|
|
or the `terminfo` database is always the preferred source when something
|
|
is unclear! Also the `tput` acronyms are usually the ones dedicated for
|
|
ANSI escapes!
|
|
|
|
I listed only the most relevant codes, of course, any ANSI terminal
|
|
understands many more! But let's keep the discussion centered on common
|
|
shell scripting ;-)
|
|
|
|
If I couldn't find a matching ANSI escape, you'll see a :?: as the
|
|
code. Feel free to mail me or fix it.
|
|
|
|
The ANSI codes always start with the ESC character. (ASCII 0x1B or octal
|
|
033) This isn't part of the list, but **you should avoid using the ANSI
|
|
codes directly - use the `tput` command!**
|
|
|
|
All codes that can be used with `tput` can be found in terminfo(5). (on
|
|
OpenBSD at least) See [OpenBSD's
|
|
terminfo(5)](http://www.openbsd.org/cgi-bin/man.cgi?query=terminfo&apropos=0&sektion=5&manpath=OpenBSD+Current&arch=i386&format=html)
|
|
under the <u>Capabilities</u> section. The *cap-name* is the code
|
|
to use with tput. A description of each code is also provided.
|
|
|
|
### General useful ASCII codes
|
|
|
|
The **Ctrl-Key** representation is simply associating the non-printable
|
|
characters from ASCII code 1 with the printable (letter) characters from
|
|
ASCII code 65 ("A"). ASCII code 1 would be `^A` (Ctrl-A), while ASCII
|
|
code 7 (BEL) would be `^G` (Ctrl-G). This is a common representation
|
|
(and input method) and historically comes from one of the VT series of
|
|
terminals.
|
|
|
|
|Name|decimal|octal|hex|C-escape|Ctrl-Key|Description|
|
|
|-------|---------|-------|------|----------|----------|--------------------------------|
|
|
|`BEL`|7|007|0x07|`\a`|`^G`|Terminal bell|
|
|
|`BS`|8|010|0x08|`\b`|`^H`|Backspace|
|
|
|`HT`|9|011|0x09|`\t`|`^I`|Horizontal TAB|
|
|
|`LF`|10|012|0x0A|`\n`|`^J`|Linefeed (newline)|
|
|
|`VT`|11|013|0x0B|`\v`|`^K`|Vertical TAB|
|
|
|`FF`|12|014|0x0C|`\f`|`^L`|Formfeed (also: New page `NP`)|
|
|
|`CR`|13|015|0x0D|`\r`|`^M`|Carriage return|
|
|
|`ESC`|27|033|0x1B|`<none>`|`^[`|Escape character|
|
|
|`DEL`|127|177|0x7F|`<none>`|`<none>`|Delete character|
|
|
|
|
### Cursor handling
|
|
|
|
-------------------------------------------------------------------------------------------------------------------------------
|
|
ANSI terminfo equivalent Description
|
|
----------------------------------------- --------------------- ---------------------------------------------------------------
|
|
`[ <X> ; <Y> H`\ `cup <X> <Y>` Home-positioning to `X` and `Y` coordinates\
|
|
`[ <X> ; <Y> f` :!: it seems that ANSI uses 1-1 as home while `tput` uses 0-0
|
|
|
|
`[ H` `home` Move cursor to home position (0-0)
|
|
|
|
`7` `sc` Save current cursor position
|
|
|
|
`8` `rc` Restore saved cursor position
|
|
|
|
:?: most likely a normal code like `\b` `cub1` move left one space (backspace)
|
|
|
|
VT100 `[ ? 25 l` `civis` make cursor invisible
|
|
|
|
VT100 `[ ? 25 h` `cvvis` make cursor visible
|
|
-------------------------------------------------------------------------------------------------------------------------------
|
|
|
|
### Erasing text
|
|
|
|
------------------------------------------------------------------------------------------------
|
|
ANSI terminfo equivalent Description
|
|
--------- --------------------- ----------------------------------------------------------------
|
|
`[ K`\ `el` **Clear line** from current cursor position **to end** of line
|
|
`[ 0 K`
|
|
|
|
`[ 1 K` `el1` **Clear line from beginning** to current cursor position
|
|
|
|
`[ 2 K` `el2`:?: **Clear whole line** (cursor position unchanged)
|
|
------------------------------------------------------------------------------------------------
|
|
|
|
### General text attributes
|
|
|
|
|ANSI|terminfo equivalent|Description|
|
|
|----|-------------------|-----------|
|
|
|`[ 0 m`|`sgr0`|Reset all attributes|
|
|
|`[ 1 m`|`bold`|Set "bright" attribute|
|
|
|`[ 2 m`|`dim`|Set "dim" attribute|
|
|
|`[ 3 m`|`smso`|Set "standout" attribute|
|
|
|`[ 4 m`|set `smul` unset `rmul` :?:|Set "underscore" (underlined text) attribute|
|
|
|`[ 5 m`|`blink`|Set "blink" attribute|
|
|
|`[ 7 m`|`rev`|Set "reverse" attribute|
|
|
|`[ 8 m`|`invis`|Set "hidden" attribute|
|
|
### Foreground coloring
|
|
|
|
|ANSI|terminfo equivalent|Description|
|
|
|----|-------------------|-----------|
|
|
|`[ 3 0 m`|`setaf 0`|Set **foreground** to color \#0 - **black**|
|
|
|`[ 3 1 m`|`setaf 1`|Set **foreground** to color \#1 - **red**|
|
|
|`[ 3 2 m`|`setaf 2`|Set **foreground** to color \#2 - **green**|
|
|
|`[ 3 3 m`|`setaf 3`|Set **foreground** to color \#3 - **yellow**|
|
|
|`[ 3 4 m`|`setaf 4`|Set **foreground** to color \#4 - **blue**|
|
|
|`[ 3 5 m`|`setaf 5`|Set **foreground** to color \#5 - **magenta**|
|
|
|`[ 3 6 m`|`setaf 6`|Set **foreground** to color \#6 - **cyan**|
|
|
|`[ 3 7 m`|`setaf 7`|Set **foreground** to color \#7 - **white**|
|
|
|`[ 3 9 m`|`setaf 9`|Set **default** color as foreground color|
|
|
|
|
### Background coloring
|
|
|
|
|ANSI|terminfo equivalent|Description|
|
|
|----|-------------------|-----------|
|
|
|`[ 4 0 m`|`setab 0`|Set **background** to color \#0 - **black**|
|
|
|`[ 4 1 m`|`setab 1`|Set **background** to color \#1 - **red**|
|
|
|`[ 4 2 m`|`setab 2`|Set **background** to color \#2 - **green**|
|
|
|`[ 4 3 m`|`setab 3`|Set **background** to color \#3 - **yellow**|
|
|
|`[ 4 4 m`|`setab 4`|Set **background** to color \#4 - **blue**|
|
|
|`[ 4 5 m`|`setab 5`|Set **background** to color \#5 - **magenta**|
|
|
|`[ 4 6 m`|`setab 6`|Set **background** to color \#6 - **cyan**|
|
|
|`[ 4 7 m`|`setab 7`|Set **background** to color \#7 - **white**|
|
|
|`[ 4 9 m`|`setab 9`|Set **default** color as background color|
|
|
|
|
### Misc codes
|
|
|
|
#### Save/restore screen
|
|
|
|
Used capabilities: `smcup`, `rmcup`
|
|
|
|
You've undoubtedly already encountered programs that restore the
|
|
terminal contents after they do their work (like `vim`). This can be
|
|
done by the following commands:
|
|
|
|
# save, clear screen
|
|
tput smcup
|
|
clear
|
|
|
|
# example "application" follows...
|
|
read -n1 -p "Press any key to continue..."
|
|
# example "application" ends here
|
|
|
|
# restore
|
|
tput rmcup
|
|
|
|
These features require that certain capabilities exist in your
|
|
termcap/terminfo. While `xterm` and most of its clones (`rxvt`, `urxvt`,
|
|
etc) will support the instructions, your operating system may not
|
|
include references to them in its default xterm profile. (FreeBSD, in
|
|
particular, falls into this category.) If `tput smcup` appears to do
|
|
nothing for you, and you don't want to modify your system
|
|
termcap/terminfo data, and you KNOW that you are using a compatible
|
|
xterm application, the following may work for you:
|
|
|
|
echo -e '\033[?47h' # save screen
|
|
echo -e '\033[?47l' # restore screen
|
|
|
|
Certain software uses these codes (via their termcap capabilities) as
|
|
well. You may have seen the screen save/restore in `less`, `vim`, `top`,
|
|
`screen` and others. Some of these applications may also provide
|
|
configuration options to *disable* this behaviour. For example, `less`
|
|
has a `-X` option for this, which can also be set in an environment
|
|
variable:
|
|
|
|
export LESS=X
|
|
less /path/to/file
|
|
|
|
Similarly, `vim` can be configured not to "restore" the screen by
|
|
adding the following to your `~/.vimrc`:
|
|
|
|
set t_ti= t_te=
|
|
|
|
#### Additional colors
|
|
|
|
Some terminal emulators support additional colors. The most common
|
|
extension used by xterm-compatible terminals supports 256 colors. These
|
|
can be generated by `tput` with `seta{f,b} [0-255]` when the `TERM`
|
|
value has a `-256color` suffix. [Some
|
|
terminals](https://gist.github.com/XVilka/8346728#now-supporting-truecolour)
|
|
also support full 24-bit colors, and any X11 color code can be written
|
|
directly into a special escape sequence. ([More
|
|
infos](https://gist.github.com/XVilka/8346728)) Only a few programs make
|
|
use of anything beyond 256 colors, and tput doesn't know about them.
|
|
Colors beyond 16 usually only apply to modern terminal emulators running
|
|
in graphical environments.
|
|
|
|
The Virtual Terminal implemented in the Linux kernel supports only 16
|
|
colors, and the usual default terminfo entry for `TERM=linux` defines
|
|
only 8. There is sometimes an alternate "linux-16color" that you can
|
|
switch to, to get the other 8 colors.
|
|
|
|
## Bash examples
|
|
|
|
### Hardcoded colors
|
|
|
|
printf '%b\n' 'It is \033[31mnot\033[39m intelligent to use \033[32mhardcoded ANSI\033[39m codes!'
|
|
|
|
### Colors using tput
|
|
|
|
<u>Directly inside the echo:</u>
|
|
|
|
echo "TPUT is a $(tput setaf 2)nice$(tput setaf 9) and $(tput setaf 5)user friendly$(tput setaf 9) terminal capability database."
|
|
|
|
<u>With preset variables:</u>
|
|
|
|
COL_NORM="$(tput setaf 9)"
|
|
COL_RED="$(tput setaf 1)"
|
|
COL_GREEN="$(tput setaf 2)"
|
|
echo "It's ${COL_RED}red${COL_NORM} and ${COL_GREEN}green${COL_NORM} - have you seen?"
|
|
|
|
### Misc
|
|
|
|
<u>HOME function</u>
|
|
|
|
home() {
|
|
# yes, actually not much shorter ;-)
|
|
tput home
|
|
}
|
|
|
|
### Silly but nice effect
|
|
|
|
#!/bin/bash
|
|
|
|
DATA[0]=" _/ _/ _/ _/ "
|
|
DATA[1]=" _/_/_/_/_/ _/_/_/ _/_/_/ _/_/_/ _/_/_/ "
|
|
DATA[2]=" _/ _/ _/ _/ _/ _/ _/_/ _/ _/"
|
|
DATA[3]="_/_/_/_/_/ _/ _/ _/ _/ _/_/ _/ _/ "
|
|
DATA[4]=" _/ _/ _/_/_/ _/_/_/ _/_/_/ _/ _/ "
|
|
|
|
# virtual coordinate system is X*Y ${#DATA} * 5
|
|
|
|
REAL_OFFSET_X=0
|
|
REAL_OFFSET_Y=0
|
|
|
|
draw_char() {
|
|
V_COORD_X=$1
|
|
V_COORD_Y=$2
|
|
|
|
tput cup $((REAL_OFFSET_Y + V_COORD_Y)) $((REAL_OFFSET_X + V_COORD_X))
|
|
|
|
printf %c ${DATA[V_COORD_Y]:V_COORD_X:1}
|
|
}
|
|
|
|
|
|
trap 'exit 1' INT TERM
|
|
trap 'tput setaf 9; tput cvvis; clear' EXIT
|
|
|
|
tput civis
|
|
clear
|
|
|
|
while :; do
|
|
|
|
for ((c=1; c <= 7; c++)); do
|
|
tput setaf $c
|
|
for ((x=0; x<${#DATA[0]}; x++)); do
|
|
for ((y=0; y<=4; y++)); do
|
|
draw_char $x $y
|
|
done
|
|
done
|
|
done
|
|
|
|
done
|
|
|
|
### Mandelbrot set
|
|
|
|
This is a slightly modified version of Charles Cooke's colorful
|
|
Mandelbrot plot scripts ([original w/
|
|
screenshot](http://earth.gkhs.net/ccooke/shell.html)) -- ungolfed,
|
|
optimized a bit, and without hard-coded terminal escapes. The `colorBox`
|
|
function is [memoized](http://en.wikipedia.org/wiki/Memoization) to
|
|
collect `tput` output only when required and output a new escape only
|
|
when a color change is needed. This limits the number of `tput` calls to
|
|
at most 16, and reduces raw output by more than half. The `doBash`
|
|
function uses integer arithmetic, but is still ksh93-compatible (run as
|
|
e.g. `bash ./mandelbrot` to use it). The ksh93-only floating-point
|
|
`doKsh` is almost 10x faster than `doBash` (thus the ksh shebang by
|
|
default), but uses only features that don't make the Bash parser crash.
|
|
|
|
#!/usr/bin/env ksh
|
|
|
|
# Charles Cooke's 16-color Mandelbrot
|
|
# http://earth.gkhs.net/ccooke/shell.html
|
|
# Combined Bash/ksh93 flavors by Dan Douglas (ormaaj)
|
|
|
|
function doBash {
|
|
typeset P Q X Y a b c i v x y
|
|
for ((P=10**8,Q=P/100,X=320*Q/cols,Y=210*Q/lines,y=-105*Q,v=-220*Q,x=v;y<105*Q;x=v,y+=Y)); do
|
|
for ((;x<P;a=b=i=c=0,x+=X)); do
|
|
for ((;a**2+b**2<4*P**2&&i++<99;a=((c=a)**2-b**2)/P+x,b=2*c*b/P+y)); do :
|
|
done
|
|
colorBox $((i<99?i%16:0))
|
|
done
|
|
echo
|
|
done
|
|
}
|
|
|
|
function doKsh {
|
|
integer i
|
|
float a b c x=2.2 y=-1.05 X=3.2/cols Y=2.1/lines
|
|
while
|
|
for ((a=b=i=0;(c=a)**2+b**2<=2&&i++<99&&(a=a**2-b**2+x,b=2*c*b+y);)); do :
|
|
done
|
|
. colorBox $((i<99?i%16:0))
|
|
if ((x<1?!(x+=X):(y+=Y,x=-2.2))); then
|
|
print
|
|
((y<1.05))
|
|
fi
|
|
do :
|
|
done
|
|
}
|
|
|
|
function colorBox {
|
|
(($1==lastclr)) || printf %s "${colrs[lastclr=$1]:=$(tput setaf "$1")}"
|
|
printf '\u2588'
|
|
}
|
|
|
|
unset -v lastclr
|
|
((cols=$(tput cols)-1, lines=$(tput lines)))
|
|
typeset -a colrs
|
|
trap 'tput sgr0; echo' EXIT
|
|
${KSH_VERSION+. doKsh} ${BASH_VERSION+doBash}
|
|
|
|
A much more sophisticated version by Roland Mainz can be found
|
|
[here](http://svn.nrubsig.org/svn/people/gisburn/scripts/mandelbrotset1.sh)
|