Sl: a steam locomotive in your terminal

nuclear_eclipse 13 years ago |

On the Sun/Solaris machines where I first worked, the `sl` command had an added bonus: it played a really loud "choo-choo" sound from the workstation's internal speaker, regardless of volume or mute settings, so you always knew when someone fat-fingered their file listings, and much laughing was had by all.

I very quickly learned to alias sl=ls in my shell rc, and it's still in there to this day, just in case...

Argorak 13 years ago |

I highly recommend the debian bug tracker on `sl`:

http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=614158

Also, for those that love their cars "pre-tuned by german engineers", there is `gti`:

http://r-wos.org/hacks/gti

_delirium 13 years ago | |

There are some nice closed bugs too. Here is an argument over whether it should support ^C by default: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=598992

ggreer 13 years ago |

Veteran: "You should apt-get install sl."

Newbie: "What does sl do?"

Veteran: (perfectly straight face) "It trains you."

jitl 13 years ago | |

Debian ships `alias sl="ls"` in the default .bashrc

martinced 13 years ago | | |

Weird. My Debian systems don't have that alias...

gee_totes 13 years ago |

I've always wondered: why is it a locomotive? Why not a penguin or something else?

Just thinking aloud here: ls stands for 'list'.... so sl stands for 'tsil'.... which is a model of a train? No, that's not it.

I think there's a missing part to this joke.

[edit] Just stepped away from my desk and took two steps and figured it out: sl = steam locomotive

pifflesnort 13 years ago | |

Regarding the penguin: sl(1) was originally written in 1992; Linux itself didn't hit 1.0 until 1994, and the Linux penguin itself wasn't introduced until 1996.

jurre 13 years ago | |

sl, steam locomotive.

Oompa 13 years ago |

I added this to Homebrew years ago, for those OS X users.

Ogre 13 years ago | |

I just installed it, thanks!

Also, brew seems to have added a beer mug emoji to the terminal output when it finishes installing something since the last time I installed anything. I didn't know the terminal (Actually iTerm 2 in this case) even supported that. Neat!

ihuman 13 years ago | |

It is also in MacPorts

Blahah 13 years ago |

When a colleague accidentally types their password to our cluster into a chat window, the first thing I do is login as them and alias ls=sl. Another fun one is to add `telnet towel.blinkenlights.nl` to their .bashrc, so on login they get to watch ascii star wars.

jaxb 13 years ago | |

... and if you unset telnet's escape char, they will watch it to the end.

nnnnni 13 years ago | | |

That's hilariously evil

endgame 13 years ago | |

It warms my heart to see that towel.blinkenlights.nl is still up.

adimitrov 13 years ago |

The one bad thing about switching to the Dvorak layout is that in Dvorak, ls is really cumbersome to type. The l isn't on the home-row, and both of them are on the right pinky. The way I do it now, it's virtually impossible to type sl instead of ls.

Typing dc instead of cd, though is still very common. And dc just mockingly tells me: "will not attempt to process directory."

(I now have `no` aliased to ls. Maybe I should alias `on` to sl.)

laumars 13 years ago |

    > The following code changes the default behaviour of ls from listing
    > files to turning your terminal into an unstoppable steam locomotive.
    > The only way to end it is closing the terminal, so use this with caution.

erm, that's easily stopped:

    [ctrl]+z
    $ pkill -9 sl

eridius 13 years ago | |

^Z will just suspend `sl`, at which point bash will immediately launch another copy. That's what the loop is for.

jlgreco 13 years ago | | |

Have you actually tried it? In neither zsh nor bash does this seem to actually be the case.

eridius 13 years ago | | |

Well no, because I didn't want to install `sl`.

But it looks like you're right. I just tried `while true; do ( echo hi; sleep 1; echo bye; ); done` and ^Z does stop the cycle.

jlgreco 13 years ago | | |

Interestingly, at least how I have zsh configured and don't have bash configured, the behavior of `fg` after suspending these is different.

With zsh when I resume the execution it continues looping. However with bash it resumes for only one more iteration.

eridius 13 years ago | | |

Yeah I would have expected `fg` to continue the loop, but it doesn't. If I put `echo $?` after the subshell in that loop, it doesn't even print when I run `fg`. It's like bash just throws away the loop entirely when I suspend the subshell.

laumars 13 years ago | | |

Bash wont immediately launch another copy because the PID is still alive (even if it is stopped).

tylermenezes 13 years ago | |

erm, no? "while true; sl; done"

X-Istence 13 years ago | | |

Hold ctrl + c down, eventually sl will have quit, and bash will quit the while loop. I've never had issues quitting out of

  while true; do echo "stuff"; done

for example.

jlgreco 13 years ago | | |

   zsh: suspended  while true; do sl; done

?

laumars 13 years ago | | |

erm, yes. I suggest you try it before commenting next time.

rdtsc 13 years ago |

Bonus info:

if you add arguments to sl like -l or -a you get a different locomotive or other effects!

Mindless2112 13 years ago |

Why alias commands to sl? The point is for it to be triggered on bad typing.

Also, the man page is worth a look -- http://manpages.ubuntu.com/manpages/precise/man6/sl.6.html

captn3m0 13 years ago |

The moving train uses js for motion. I stripped that part to http://jsbin.com/ujizup/1

orvtech 13 years ago |

I did a little video on this a couple of weeks a go with a mini how to for Fedora users https://news.ycombinator.com/item?id=4766611

frankblizzard 13 years ago |

first saw this thing around 12 years ago on an AS/400 terminal. Our neckbearded Lead Programmer was supposed to have programmed it in RPG but probably this thing is even older?

Argorak 13 years ago | |

The source downloaded from the authors page[1] lists the following modification times:

    [ skade sl ] ls -la *
    -rw-r--r-- 1 skade staff  331 Jul 22  1998 Makefile
    -rw-r--r-- 1 skade staff  417 Jul 22  1998 README
    -rw-r--r-- 1 skade staff  689 Jan 18  1994 sl.1
    -rw-r--r-- 1 skade staff 7.0K Jul 22  1998 sl.c
    -rw-r--r-- 1 skade staff 4.1K Jan 18  1994 sl.h
    -rw-r--r-- 1 skade staff  980 Jan 18  1994 sl.txt

So, it is almost 20 years old.

[1] http://www.tkl.iis.u-tokyo.ac.jp/~toyoda/index_e.html

benhalllondon 13 years ago |

Great, excellent, fun.

But, clearly, it should run 'ls' after doing its choo choo?

cliffbean 13 years ago | |

That is optimizing for the short term. "When I've run sl, I clearly wanted ls, so you should give me that (even if you also punish me)."

Optimizing for the long term is also plausible. "Don't reward me for making mistakes (even if you also punish me) because it'll dilute my muscle-memory training, and I'll be more likely to make mistakes in the future."

Neither of these is inherently more correct than the other. The long term has more uncertainty, but greater potential rewards. We just have to make a judgment call.

I tend to favor the long-term approach for sl. I can't easily quantify how valuable my stricter muscle-memory training will be, but I can imagine the possibility of a significant upside if I actually become a more precise typer. Also, the worst-case downside just isn't that bad -- retyping ls just isn't that hard.

rmk2 13 years ago | |

Well, this forces you to type 'ls' again, giving you another chance to see the awesome locomotive! ;)

philwelch 13 years ago | |

The Unix philosophy is that a program should only do one thing. sl only does one thing.

minos 13 years ago | |

One could use a shell alias, a function or something similar for that.

ricket 13 years ago | | |

alias sl='sl;ls'

niggler 13 years ago |

"Note: I actually didn't use a marquee for this. The one good use for one, and I missed it. Damn."

Is this even a good example for using html marquee?

prezjordan 13 years ago |

How did you get this in the main repositories? I'm curious what the process is for something like that.

blablabla123 13 years ago | |

According to someone else's comment this thing is at least 20 years old. AFAIK these things go by popularity, after all any sort of game is also non-productive...

davidroberts 13 years ago |

I just installed it on my Raspberry Pi. It's in the Raspian repository too!

nilsbunger 13 years ago |

If you're on a Mac with homebrew, "brew install sl" will get you there!

mbubb 13 years ago |

Not the same thing but "apt-get moo" on a Debian based box is fun...

dogface 13 years ago |

Oh come on! This isn't news. I was using sl fifteen years ago.

mostly_harmless 13 years ago |

alternatively if you are really evil, you can 'alias ls="rm -rf"'

jzoidberg 13 years ago |

We need one for "got"

kmf 13 years ago | |

Delivered.

https://github.com/imkmf/got

Watabou 13 years ago | | |

Okay that is freaking awesome. I now have GoT's theme playing in the terminal.

This may actually make me misspell git even more.

fnordfnordfnord 13 years ago | |

Got,

Got Milk?, Displays Got Milk? Advert. Boring

GOThic, Changes terminal font to Gothic?

GoT, Game of Thrones, Decapitates user?, Automatically fires up BitTorrent client and grabs latest episode? Plays ASCII art GoT episode? Cat's all of GRRM's GoT novels into your terminal? (That'll teach you).

jaxb 13 years ago | | |

A shitogram for modern age.

systematical 13 years ago |

had to apt-get sl

barkingcat 13 years ago |

on os x - brew install sl brings it in.