Provided by: neo-cli_0.6.1-1_amd64 
NAME
neo - simulate the digital rain from "The Matrix"
SYNOPSIS
neo [OPTIONS]...
DESCRIPTION
neo recreates the digital rain effect from "The Matrix". Streams of random characters will endlessly
scroll down your terminal screen. There are many differing depictions of this effect throughout the
Matrix franchise. neo attempts to closely mimic the scene from "The Matrix" where Cypher explains the
code to Neo. It imitates some of the finer details such as the characters used (half-width katakana),
uneven colors, color palette, glitching, and flickering.
The digital rain is made of many "droplets". Each droplet scrolls vertically down a column. There can be
multiple droplets in each column. Some characters on the screen are "glitched" - their values will change
randomly until they are erased. The bottom of each droplet is a bit brighter than the rest.
You can run neo without any arguments, but it has many options to customize it to your liking. It can
also respond to key presses (try pressing a number!), and it accepts a color file (see the "COLOR FILE"
section below), which allows neo to display user-defined colors. neo will use Unicode characters by
default if it detects a locale that supports UTF.
OPTIONS
neo takes options in two forms: short and long. Short options cannot include an equal sign but long
options can. Example for -S/--speed:
These will work:
-S 16
--speed 16
--speed=16
These will not:
-S=16
--S 16
-a, --async
Makes each column of characters scroll at an independent speed. Each column's speed is still
limited by the -S/--speed arg. All droplets in a column will always scroll at the speed.
-b, --bold=NUM
Controls if and how neo displays bold characters. 0=off, 1=random (default), 2=all.
-C, --colorfile=FILE
Read the colors from a file. This option is mutually exclusive with the -c/--color and
--colormode=0 options. See the "COLOR FILE" section below for more info.
-c, --color=COLOR
Sets the foreground text color. This option is mutually exclusive with the -C/--colorfile and
--colormode=0 options. The available colors are: green, green2, green3, yellow, orange, red, blue,
cyan, gold, rainbow, purple, pink, pink2, vaporwave, and gray.
-D, --defaultbg
Use the default terminal background color. This option is mutually exclusive with the
-C/--colorfile and --colormode=0 options.
-d, --density=NUM
Controls how many droplets will appear onscreen. NUM is a decimal number. Its default value is
1.0. Values greater than 0.0 but less than 100.0 are allowed. However, values in the range [0.25,
4.0] will probably look best.
-F, --fullwidth
Use two columns per character. This option is useful when displaying characters that take two
columns to display such as Greek and full-width katakana.
-f, --fps=NUM
Sets a frame rate target. By default, neo will run at 60Hz. neo does not attempt to query the OS
for any display info. So it can't match your monitor's refresh rate by default unless it happens
to be 60Hz. Lower frame rates will reduce CPU usage and improve battery life on portable devices.
-G, --glitchpct=NUM
Sets the percentage of characters onscreen that glitch. NUM is a decimal number between 0.0 and
100.0 inclusive. The default value is 10.0 (i.e. 10%).
-g, --glitchms=NUM1,NUM2
Controls how often the characters on screen glitch. A "glitch" refers to when a character changes
into another. Each glitch is accompanied by a flickering of the character's color if colors are
enabled. After each glitch, neo will wait for some time before doing the next glitch. The time it
waits is chosen randomly to be between the two values provided (inclusive). NUM1 and NUM2 are
positive integers that represent milliseconds. Their default values are 300 and 400.
-h, --help
Shows the help message.
-l, --lingerms=NUM1,NUM2
Controls how long characters stay onscreen after they finish scrolling. For each column, neo will
pick a random value between NUM1 and NUM2 inclusive. NUM1 and NUM2 are positive integers that
represent milliseconds. The default values are 1 and 3000.
-M, --shadingmode=NUM
Controls how neo assigns color values to characters on the screen. 0=random (default),
1=gradient.
-m, --message=STR
Displays a message in the center of the screen. The message is gradually uncovered as characters
stream past it. This effect is similar to the title reveal in the movies. The message should be
surrounded with double quotes. neo parses arguments using getopt_long(), which does not have
Unicode support. So, unfortunately, this argument only accepts simple ASCII text. The message
will not display well if you also use the -F/--fullwidth option. To unveil the message faster,
the following options may help:
neo -m "the message" --speed=12 --density=3 --lingerms=1,1 --rippct=0
-p, --profile
Turns on the profiling mode. This mode functions as normal except it times how long each frame
takes and writes the values to a file called "time_profile.txt" in the current working directory.
-r, --rippct=NUM
Sets the percentage of droplets that stop scrolling before reaching the bottom of the screen. NUM
is a decimal number between 0.0 and 100.0 inclusive. The default value is 33.0 (i.e. about a
third).
-S, --speed=NUM
Controls how fast characters scroll down the screen. NUM is a decimal number that sets the number
of characters drawn per second. The default value is 8.0. If -a/--async is used, this option sets
an upper bound on the value chosen for each droplet's speed.
-s, --screensaver
If this option is set, neo will exit on the first key press.
-V, --version
Displays the version, build date, copyright, and license.
--chars=NUM1,NUM2
Tells neo to display Unicode characters between NUM1 and NUM2 inclusive. NUM1 and NUM2 are
Unicode code points in hexadecimal (e.g. 0x1F030). This argument can be used multiple times. If
--charset is not used, neo will only use the values provided by this option. If a charset is also
specified, neo will use both the charset and the characters provided by this option.
--charset=LANG
Sets the charset that is used to draw characters onto the screen. It can be combined with the
--chars option. The supported charsets are: ascii, extended, english, dec, decimal, digits, punc,
bin, binary, hex, hexadecimal, katakana, greek, cyrillic, arabic, hebrew, devanagari, braille, and
runic.
--colormode=NUM
Sets the color mode. The accepted values are 0, 16, 32, and 256. 0 disables color (i.e. mono). 16
selects 16 colors. 32 selects 32-bit color. 256 selects 256 colors.
--maxdpc=NUM
Sets the maximum number of droplets per column. The default value is 3.
--noglitch
Disables character glitching.
--shortpct=NUM
Sets the percentage of shortened droplets. If a droplet is not shortened, it will extend from the
top of the screen to final line, which is often the bottom of the screen but not always (see also:
-r/--rippct). NUM is a decimal number between 0.0 and 100.0 inclusive. The default value is 50.0
(i.e. 50%).
KEYS
You can press keys while neo is running to control its behavior. The key bindings cannot be changed
without modifying the program code. Some keys can be held to increase their effect (e.g. holding UP
increases speed further).
Here are the available key controls:
´SPACE' - clears the screen
´UP' - increases the scrolling speed
´DOWN' - decreases the scrolling speed
´RIGHT' - increases the number of characters that are glitchy
´LEFT' - decreases the number of characters that are glitchy
´TAB' - toggles the shading mode between random and gradient
´ESC' - exits neo
´+' - increases the number of droplets onscreen
´-' - decreases the number of droplets onscreen
´a' - toggles asynchronous droplet speed
´p' - pauses neo
´q' - exits neo
´1' - sets the color to green
´2' - sets the color to green2
´3' - sets the color to green3
´4' - sets the color to gold
´5' - sets the color to pink2
´6' - sets the color to red
´7' - sets the color to blue
´8' - sets the color to cyan
´9' - sets the color to purple
´0' - sets the color to gray
´!' - sets the color to rainbow
´@' - sets the color to yellow
´#' - sets the color to orange
´$' - sets the color to pink
´%' - sets the color to vaporwave
COLOR FILE
neo can read a file that specifies the background color and all the foreground colors. The file is given
via the -C/--colorfile option.
You can write comments using "//", "#", ";", "*", or "@". Comments can go on separate lines or after the
data on any line. The first line that is not blank or a comment should be the version string. The version
string line should look like:
neo_color_version N
where "N" is the color file version number, which is currently 1. The version string is optional, and if
it is omitted, then neo will assume that the file adheres to the latest version's format. This could
potentially break old color files. Ye have been warned! neo will try to maintain backwards compatability
with older color file versions so long as their version is actually given.
Each data line in the file describes a color. The first line is the background color. Each subsequent
line describes a foreground color. Each file must contain at least two lines: one for the background and
one for the foreground. Typically, you will want to put the foreground colors in order of ascending
brightness. neo will not sort the colors. The last color should usually be very bright (e.g. white).
Each data line in the file specifies one value or four values. If only one value is given, it is treated
as a 16 or 256 terminal color code (e.g. 16 is black). If four values are given, the first is treated as
a 16/256 color code and the other three are the RGB components of the 32-bit color. Each component is a
value from 0 to 1000, which closely mimics how ncurses handles color. Each value is separated by a comma,
and whitespace is allowed.
If more than one value is given on a line, then all four values must be given. Lines do not all have to
have the same number of components i.e. some lines can just specify the 16/256 color code while others
can specify all four values.
On most systems, if a value of "-1" is provided for the 16/256 color code, this will set the color to the
system default. This can be useful if you want to keep the default background.
All ncurses implementations should allow you to override at least the first 256 colors, assuming your
terminal supports it. Some will let you override even more than that. ncurses should restore all colors
back to their previous state as long as neo exits cleanly.
If either of the 16 or 256 colormode options is used, all 32-bit RGB components in the color file will be
parsed if they are given, but they will be unused.
Example 1: Blue text on a red background using only 256 color codes
196
21
Example 2: Different shades of purple text on a yellow background with some 32-bit color components
228,917,888,59
54
92
129,750,963,128
Example 3: Default background and various shades of green using only 256 color codes
-1
34
40
46
82
231
PERFORMANCE
neo can have two main performance issues: high CPU utilization and stuttering. A terminal emulator with
GPU acceleration (e.g. Alacritty) may significantly improve these issues. The CPU utilization by neo
itself is fairly low, even at high frame rates on large screens. However, your terminal emulator may use
substantial CPU resources to draw everything. Without a fast terminal emulator, this application may use
up a whole CPU core or three.
Sometimes the text will not scroll smoothly. Again, a fast terminal emulator will probably help. You will
also typically want the frame rate (i.e. --fps) to be evenly divisible by the character speed (i.e.
-S/--speed). Sometimes, the glitching effect will lead to stuttering because a substantial number of
characters onscreen will have to be redrawn. Reducing the glitchiness (i.e. --glitchpct) or disabling
glitching (i.e. --noglitch) may help.
If you experience performance issues, here are some things to try:
1. Use a GPU-accelerated terminal emulator
2. Run neo on a smaller screen/window
3. Reduce the frame rate (e.g. --fps=30)
4. Reduce the number of droplets onscreen (e.g. -d 0.5)
5. Reduce the character speed (e.g. --speed=6)
6. Disabling glitching (i.e. --noglitch)
7. Disable colors (i.e. --colormode=0)
8. Disable bold characters (i.e. --bold=0)
9. Disable Unicode characters (i.e. --charset=ascii)
Here is a "potato mode" config that should perform well on most systems:
neo --fps=20 -d 0.5 --speed=5 --noglitch --colormode=0 --bold=0 --charset=ascii
EXAMPLES
Example 0: Just run it
neo
Example 1: Sets a faster, asynchronous scrolling speed with 256 colors
neo -S 12 -a --color=green3 --colormode=256
Example 2: Red text with a custom message and Cyrillic characters
neo --color=red --charset=cyrillic -m "IN SOVIET RUSSIA, COMPUTER PROGRAMS YOU!"
Example 3: Displays golden Greek characters that are full-width
neo --color=gold --charset=greek -F
Example 4: Uses --chars to draw Unicode dominoes
neo --chars=0x1F030,0x1F093 --fullwidth
AUTHORS
Written by Stewart Reive
REPORTING BUGS
Create an issue on GitHub: https://github.com/st3w/neo
COPYRIGHT
Copyright © 2021 Stewart Reive
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software:
you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.
DISCLAIMER
This program is not affiliated with "The Matrix", Warner Bros. Entertainment Inc., Village Roadshow
Pictures, Silver Pictures, nor any of their parent companies, subsidiaries, partners, or affiliates.
SEE ALSO
locale(1), localectl(1)
AFTERWORD
You get used to it. I... I don't even see the code. All I see is blonde, brunette, redhead. Hey! You
uh... want a drink? :)