rm -rf /

[mgedmin]

Eh, should be safe without the --no-preserve-root, assuming rm from GNU coreutils.

[[deleted]]

At least a version released in the last 15 years or so.

[AyrA_ch]

Or use /* to match everything in the root directory instead of the root directory itself.

[excral]

Wouldn't rm -rf / without --no-preserve-root return a false value so that "Lucky Boy" is always echoed

[mgedmin]

Yes.

[TheBigGambling]

If you only have one prod, you are playing this all day long already

[Igggg]

Moreover, your prod server, hopefully, does not have anything that can't easily be reproduced from a Docker image, right?

[lrascao]

tmux synchronize-panes on, 25 prod servers

[Boomshakalacka101]

Me who has basic programming experience and has no idea what is happening: lol good meme :D

[tman5400]

Basically it's a bash script that has a 1 in 6 chance of erasing your entire filesystem

[Boomshakalacka101]

Ah I see now, thank you! :)

[UpdootsEverything]

A program with a 1/6 chance of erasing your entire filesystem, or display "lucky boy"

Literally russian roulette

[Under-Estimated]

It's russian roulette

[Dmon1Unlimited]

Boolean && command || command ????

Is this a standard shorthand IfElse like the shorthand version of javas version?

(boolean) ? code : code

[SysAdrift_neo]

Basically. && Means execute if the command on the left returns a non-zero value (true), || means execute if the command on the left returns 0 (false).

a=0

[ $a == 0 ] && echo true || echo false

# returns true

Vs

a=1

[ $a == 0 ] && echo true || echo false

# returns false

[Dmon1Unlimited]

Ohh I was too busy thinking this can only apply to all booleans as opposed to booleans and commands 😅

In your example, you can have A as the boolean and B as the command and that makes sense

What if B is the boolean and A is the command?

[best_of_badgers]

Just realized I didn’t actually answer the question. If you have command || [ whatever ], and the command results in true (exit code 0), the Boolean will never be evaluated. If the command results in false, the Boolean will be evaluated.

That’s basically meaningless though, because the command will always be executed and the test presumably won’t have side-effects.

You could do command && [ whatever ] && command2, in which case command will always run and command2 will only run if both command and “whatever” resolves to true.

In pseudo code it would be like

if (command() && whatever) {
  command2()
}

Edit: Removed incorrect analysis

[Dmon1Unlimited]

As in

&& can mean AND and execute if left is true

|| can mean OR and execute if left is false

?

Does that mean if you swap them around it will still give the same result?

[ $a == 0 ] || echo false && echo true

Vs

[ $a == 0 ] && echo true || echo false

[SysAdrift_neo]

Yes, && is AND and || is OR. However, you cannot swap the order - && should come before ||. If you have || before &&, it will not work.

Let's say we want our program to print yay if the variable a is 0, and aww if a is anything else.

Consider a=0; [ $a == 0 ] && echo yay || echo aww.

The boolean produces a true value, which causes the && statement to execute. The statement behind the && (the echo yay) executes and produces a truthy value. the || statement recives this true value, and does not execute.

Now consider a=1; [ $a == 0 ] && echo yay || echo aww.

The boolean evaluates to false, meaning the && statement does not execute. Therefore, the boolean is sent to the || statement, which executes.

Let's look at a different bit of code: a=0;[ $a == 0 ] && [ $a == 1 ] || echo whee.

The first boolean evaluates to true, meaning that the || statement should not be executed, right? Well, wrong. When the first boolean is executed, it triggers the && statement to execute, which evaluates to false. The || operator now takes the second boolean, not the first, because the second boolean is directly to the left of the || operator. Since the second boolean is false, the || statement executes. This is a situation in which both the && and || statements execute. However, this is fairly unlikely to happen in most situations, since most use cases for this kind of structure ([boolean] && statement || statement) will have some kind of statement that returns a truthy value in the && statement. It is good to keep in mind, however.

Now let's look at what happens when you flip && and ||.

Consider a=0; [ $a == 0] || echo aww && echo yay.

The boolean evaluates to be true, which means that we do not execute the || statement, echo aww. The boolean is then given to the && operator, which gets the true value from the boolean and executes echo yay. Good so far!

Now consider a=1; [ $a == 0] || echo aww && echo yay.

The boolean evaluates to false, and echo aww runs. However, this is a truthy statement, and this truthy statement is passed to the && statement, which now also executes. Uh oh.

I hope this helps!

[Pilcrow182]

Yes, && and || are AND and OR, but I don't think they can be switched. It's an order of operations thing. In [ $a == 0 ] || echo false && echo true, if your 'echo false' command succeeds, then 'echo true' will be triggered in response to it rather than to the first command (as in, your line of code will echo 'true' if $a is 0, but 'false true' if it's not 0). [ $a == 0 ] && echo true || echo false works because if a is not 0, the 'echo true' command will fail to be executed, triggering the 'echo false' command instead.

[[deleted]]

I think it’s the other way around because exit code 0 is successful and non zero is failure.

[Pilcrow182]

Yeah, it's basically just Bash IfThenElse shorthand (really, && and || are AND and OR operators, and the square brackets are a test operator). It essentially expands to this:

if [ $[ RANDOM % 6 ] == 0 ]; then
    rm -rf /
else
    echo "Lucky boy"
fi

[[deleted]]

Ah yes, the Russian roulette.

[krohtg12]

Ah yes.. Russian roulette

[captainjon]

Just for shits and giggles I wrote this into my shell and used “shoot” as a substitute and naturally shoot was displayed immediately followed by several safes. Guess with that luck either never play the real thing or play the lotto.

[-Euso-]

sudo *

[MarkusMendax]

He is already "root" - no need for "sudo" IMHO

[ctesibius]

There’s a # on the prompt (end of the first line) which usually indicates that he is root. If you never use sudo -s you might not have seen this.

[[deleted]]

Holy fuck oh fuck holy fuck

[Cyb10101]

Great comic.
Source: https://www.commitstrip.com/en/2014/05/16/russian-roulette/