kugg
Rebanein linux you can use the evil bird emoticon (:>) to destroy files, eg `:> important_document.txt`
the bird will eat the file and leave it completely empty!
Leah 
@rebane2001 hmm I suppose thats because its writing nothing into the file but I dont understand the reason for the
Id assume it works without?
Im guessing
: (I mean yeah it does make the face but from a commands perspective I mean)Id assume it works without?
Im guessing
: is ignored or perhaps written into the file?
Lambda@ChaosKitsune @rebane2001 : is the no-op built-in in POSIX shells.
Pink Rhododendron@lambda @ChaosKitsune @rebane2001 does that like actually run the no-op in assembly//machine level ?? or actually do nothing and return 0 ??
@pinkRhododendron @ChaosKitsune @rebane2001 the latter, there's no reason the *implementation* of the shell built-in would have to use an extra machine instruction that does nothing (though maybe the compiler sneakily inserts one anyway, e.g. for alignment reasons!)
dakkar@ChaosKitsune https://www.gnu.org/software/bash/manual/bash.html#index-_003a
the colon is a shell command that does nothing
it's often used to perform expansions with side-effects, like:
: ${ARGUMENT:=default value}
: ${MUST_BE_SET:?error message}@rebane2001
Jose Andrade@dakkar @ChaosKitsune @rebane2001 also infinite cycles:
while :
do
<whatever>
Done
@jcpandrade ha! I tend to do
(yes, I know that involves a fork+exec, but if we cared about speed we wouldn't be writing shell)
@ChaosKitsune @rebane2001
while true because it reads better to me(yes, I know that involves a fork+exec, but if we cared about speed we wouldn't be writing shell)
@ChaosKitsune @rebane2001
@dakkar I used the true but... : is faster and easier to type... Just being lazy, I admit. @ChaosKitsune @rebane2001
always tired@dakkar @ChaosKitsune @rebane2001 @jcpandrade
I'd guess many shells execute true as built-in too.
@project1enigma oh, you're right (I hadn't noticed), bash has indeed
@ChaosKitsune @rebane2001 @jcpandrade
true and false as builtins!@ChaosKitsune @rebane2001 @jcpandrade
Paco@pacostegosaurus yep!:(){:|:&} is equivalent to:
function :() {
: | : &
}or, changing the name:function bomb() {
bomb | bomb &
}which calls itself twice (piping the non-exsitend output of the first call to the second) as a background process, therefore doubling the number of running processes every time (each process exits immediately, but it still bogs down the machine)
@ChaosKitsune @rebane2001
@dakkar @ChaosKitsune @rebane2001 Nice! I remember reading about this some time ago but somehow I missed that : was not only a valid identifier but actually a standard command
Odd@ChaosKitsune @rebane2001 : is a no-op with no output, which is then redirected to the file.
See: https://stackoverflow.com/questions/3224878/what-is-the-purpose-of-the-colon-gnu-bash-builtin
See: https://stackoverflow.com/questions/3224878/what-is-the-purpose-of-the-colon-gnu-bash-builtin
Omnivore':' returns 0 (meaning true). I just checked and '>' clears the file with no input. So, yes, the ':' is just decorative.
ΠΡ οΏ½οΏ½@ChaosKitsune it's a bash builtin
$ help :
:: :
Null command.
No effect; the command does nothing.
Exit Status:
Always succeeds.
Jeff@ChaosKitsune @rebane2001 : is the null command in the POSIX shell standard. It's a built-in that outputs nothing and exits immediately with a status of zero (effectively the same as /bin/true).
So the shell parses ':> afile' as "null command with output redirected to afile"
kaaswe@pinkRhododendron @rebane2001
I would have also created an alias for the hungry cat to echo out on console
Burp, mjao
I would have also created an alias for the hungry cat to echo out on console
Burp, mjao
>>>>>>>@rebane2001 I feed my evil bird junk files twice a day so they don't get hungry and start eating files I need
two@rebane2001 thanks i was hungry :>
Cenobyte 
@rebane2001 This is awesome for clearing out files. Some log files when you're trying to isolate. Love learning new commands. Thank you!
draeath@cenobyte @rebane2001 I usually just use
truncate or echo "" > whatever but this is a lot more terse. I like it.@draeath @cenobyte @rebane2001
With echo "" you don't make an empty file though. It's a file with one octet (newline) then.
@project1enigma @cenobyte @rebane2001 true unless you pass the argument not to add that... But at that point things are getting silly and there's definitely better ways. But in most of the things I work with, a truly empty file and a file with only a newline in it are close enough to equivalent.
Benjamin Balder Bach@rebane2001 it doesn't eat worms `~` β
```
$ :> ~
bash: /home/user: Is a directory
```
Leeloo
pyro gaming
bartholin (war, war never changes arc)@rebane2001 The nice bird is named sudo rm -rf /
Lucy Pinder@rebane2001 It's a cool fact
Silo πΊπΈπ€πΊπ¦
Alesandro Ortiz π΅π·π³οΈβπ@rebane2001 New "Press Alt+F4 to win" just dropped.
BeckyThanks! Iβve learned AND cemented :> as evil bird
Narf (Fran Regen Period)
det (ΞΈΞ)@rebane2001 i would draw this if i had the energy to do so and also the art skills to draw that well enough to not have my perfectionist brain tear into me
K. Ryabitsev-Prime π@rebane2001 technically, it will only steal your file, not destroy it. Which, I guess, means that :> is a corvid.