Randomness in Bash and Linux: shuf and $RANDOM XD

[@bool2max]

2:10 that's not arbitrary at all, that's the maximum value of a signed 16bit (2byte) integer

[@henrymalinowski5125]

@@nilsirl arbitrary - "based on random choice or personal whim, rather than any reason or system"

[@theredtechengineer1480]

Gabriel Sinca what about unsigned 7 bit ascii?

[@martinprochazka3714]

You are breaking the randomness by using the modulo "hack". For example if you have generator giving you numbers 0...5 and you need 0..4 so you modulo it by 5. It maps numbers this way 0-0, 1-1, 2-2, 3-3, 4-4, 5-0, as you can see there is double chance that 0 is generated relative to other numbers (in this case). So be careful with this method :)

[@vmisev]

Thanks for the tip on modulo for $RANDOM - I like that very much :) BTW, you are correct about shuf in FreeBSD - it's in ports (sysutils/shuf); and gshuf is installed with GNU coreutils (sysutils/coreutils). jot(1) is tool that's in base, but options are different, e.g. "-r" in jot(1) "generates random data instead of the default sequential data"

[@geremachek]

"Core yootuls"

[@c.deg.7982]

Now start saying random things in the tutorial, and maybe random people with a dark complexion, from random alphabet soup institutions that emit random rays of light in the night will come to visit your location on a random day!

[@deidara_8598]

Cryptographically secure randomness isn't just about entropy, it also has to do with the source of randomness. A Mersenne twister has high entropy, but the randomness is seeded and deterministic, so the security of keys generated with that type of randomness will hinge purely on the seed chosen, which is undesirable. /dev/urandom takes its randomness from several sources which collectively makes it extremely hard to predict, which makes it optimal for generating secure cryptographic keys.

[@deidara_8598]

The $((RANDOM % 10)) has a problem in that it has a slight bias towards 0-6 over 7-9. This is because the RANDOM variable generates numbers within a specific range, and unless the max of that range is perfectly divisible by the modulus, there will be a slight bias towards the remainder of the modulus divded by the max range. Another way to visualize it is to imagine RANDOM generates all numbers within its range with equal probability, now imagine taking the modulo of every number within that range, then count up the results you get, what you will discover is that the lower range of numbers will have a slightly greater advantage than the larger numbers. For a modulus of 10 is this barely noticable, but try it with 1,000 or 10,000 or 20,000, and you will start to notice the bias more clearly

[@cookiedestroyer402]

>Luke in live stream 3 days ago >"don't ever use cat its for brainlets use grep + inputs etc. >luke today >cat cat cat cat cat cat my brain hurts

[@rexevan6714]

We are all hypocrites

[@thebackofdoctormanhattanshead]

He was probably talking about searching for stuff with grep IE don't do cat file | grep -i searchterm, whereas here he's using it as a pager.

[@perseusarkouda]

while true; do v1+=lol; cat

[@evelioguaperas]

The noose emoji we've been waiting for lmao

[@ianb1923]

This comes out 6 days after I finish my python script to generate customizable random numbers. Nice

[@AnastasisGrammenos]

@@khai96x If shuf has the same quality of code as the other coreutils I doubt you can make a python copy that works faster. Since shuf is just 600 lines of C, that figures out

[@mononix5224]

@@khai96x I disagree about the cryptic part, because it is intuitive to me. Now I don't know about the speed of python, but I've head a lot of people complain about how slow it is :/

[@ChungusAm0ngus]

Well, I guess fortune is useless now.

[@wherestheshroomsyo]

the modulus trick, isn't perfect by the way but it's close. Use shuf if you need perfect.

[@GabrielPiveta]

thanks, now i can make my god words! just like terry!!!!

[@Dusta_Rhymes]

lol xd randum bashisms UwU hehe ~~

[@jan_harald]

function randomnumber { shuf -i ${1:-1}-${2:-10} -r -n 20|shuf -n1; } very simple random number function with shuf, with optional range specification, probably better than $RANDOM anyway ;P makes repeating pool of 20, then chooses one of them, defaults to range 1-10 if you want to bother, you can make it so that one argument = second range argument, but if both then first = first, and such... kinda pointless tho...

[@ianpan0102]

Hey Luke! Which font are you using in the terminal? I really like it.

[@b0ba_884]

I really like your content and because of your tutorials and LARBS i have i3 with arch know but i was thinking to move to gentoo, what is your opinion and which one is better

[@bendover4728]

This is just great! Could you please elaborate on AWK utility? Thank you a lot!

[@antuacharjee9145]

Make a video about awk command

[@GNU_Linux_for_good]

08:00 Any chance Luke will share his wonderful emoji file with the rest of the community?

[@jasperzanjani]

shuf is bloatware, real players use sort -R

[@andrez76]

Pardon the random question, but what keyboard do you use? Thanks.

[@davidkeys4284]

Unicomp

[@thomasschlieter5281]

Thanks, I learned something new.

[@sarundayo]

Wonder if it can be used to randomly look up the weather on different parts of the world.

[@xGOKOPx]

why not

[@duyhuyhoangdo4183]

what is your bash extension?

[@Iglum]

When are you gonna use Amazon polly to make a creepy meme voice for the videos?

[@SimGunther]

Is BusyBox a meme or is it a viable coreutil replacement? Hmmmm.....

[@distroverse]

For small devices and containers (like Docker), Alpine Linux is a popular option and it uses Busybox. If you like being more "POSIX compliant"/correct/minimal than it is nicer option than GNU coreutils which have a lot of extensions and is so **** bloated. For example ls.c from coreutils is 5200 lines where busybox is 1000 or cp.c is 1200 and busybox 200.

[@PedroSantos-ru9uw]

which font are you using in this video?

[@luka95kovach]

Hey Luke, are you using polybar on your machine or i3status? It looks really nice...

[@jan_harald]

why'd you put XD in title, lol also as mentioned before, why $RANDOM if you can `strings /dev/urandom|grep "[0-9]"|head -c100` or such ;P

[@InNominePraxis]

package that allows printing color emojis in i3blocks?

[@elsholz2365]

Remove random directory from root?

[@purplewarrior1830]

NO

[@billyblackburn864]

where can I get the file with all the emojis?

[@Clutter.monkey]

PSEUDOrandom

[@MartinsTalbergs]

not true

[@aedd3307]

Everything in computers is pseudorandom, its just giving some OS variables as a seed to an algorithm that will produce the same seed given the same seed

[@kattengustav1]

Upload the emoji DB!!

[@muellerhans]

Why isn't your time emoji?

[@YanPashkovsky]

You're wrong, dev random is really random and can be used in cryptography , urandom is pseudorandom

[@forcebewhithyou94]

Good stuff, men can you do, like an explanation of the man page, every time that I review one, is like language from another plane or trying to confuse the explanation, is embarrassing to me no to understand anything in there, but also this babble also is embarrassing to somebody that claim is an explanation, for a user with no expertise trying to get help.......

[@hielke2332]

Take a look at tldr for shorter and simpler explenation of commands.

[@Sp0nge5]

I thought you'd switched to Fish?

[@GeorgijTovarsen]

$((arithmetic))

[@mallock8529]

this is epic colon three

[@gavinvales8928]

New computer?

[@___xyz___]

"random"

[@rajufelix3070]

love you man

[@wiswis]

not as random as /dev/random 🤦‍♂️

[@lachlangreen9766]

1st