Ubuntu Day

Spanish only: GNU/Linux, Guía de Supervivencia - Versión Ubuntu Day

Released under WTFPL if you care to know. Source code to be available soon too.

CM WTF

Seen on a cablemodem's configuration page:

<form action="http:/loginData.htm" method="GET">

Long version: The other day, while stranded on a CLI (using ssh) I did a wget $IP, to see a modem's status web page. I'd have thought an electronic device (which, obviously, is much more difficult to upgrade than a software product, and that's difficult enough as it is) is a little bit better tested than that. I should have known better by now.

sed magic: a simple guide

The other day I had to create one of those "enum to string" functions. They really suck, always getting out of sync, so I made a script to auto-update the header file containing this function... just add a target to the makefile and you're done!

Anyway, this is the part of the script I came up with to get the enum elements:

cat enum_definition.h | sed -n '/enum OID/,/};/ s/(.*)/1/p'

Nice voodoo, isn't it? How the hell are you supposed to understand that? Well, you're not, sed is write-only-code, but you can try reading http://www.grymoire.com/Unix/Sed.html#toc-uh-25, a great sed introduction.

Have fun!

gdb: graphic (tui) mode

A little known fact about gdb is that you can use it in graphics mode, called TUI. Yes, you can obviously use DDD or a similar front end but that's not even nearly as cool as using a console based GUI (!), is it?

The easiest way is to start gdb like this:

gdb -tui

That will display the usual gdb console plus a code listing, similar to the code listing you get using the "list" command but shown in another window. Alternatively you can press C-X C-A (both, in that order) while in gdb to switch between TUI mode and back.

Don't know enough about gdb? Read http://beej.us/guide/bggdb/, a great gdb intro.

First Ubuntu Day in Buenos Aires

On sat. 26 of september, this saturday, I'll be on the first Ubuntu Day in Buenos Aires. Of course, I'll be a speaker there, it's time to undust the old GNU/Linux Survival Guide Again.

See you @ Ubuntu Day :)

Vim Tip: Rot 13

Are you still puzzled by last week's C++ question, yet you are too lazy to actually search for a Rot13 decoder OR use gcc to check if it works? Well, Vim can do the trick, just use g? to convert text to Rot13

You may combine it with block selection or you can just convert the whole damn thing using "ggg?G". gg goes to the beggining, g? converts to rot13, G goes to the end.

This is all very nice but I'm still trying to figure out a way to convert back from rot13 to normal text, can anyone provide a clue?

Console foo: Scheduling commands

You can easily schedule a command using "at", which recognizes a nicely formatted date string.

For example:

$ at today 3:00 AM

This will open a prompt. So, for example:

$ at today 3:30 PM
> wget foobar.com/a_huge_file
> C-D

Will schedule a download of a huge file, today at 3:00 AM. Nice, isn't it?
To check the whole list of accepted formats check the man for at.

One last note: at will "remember" the current environment variables, so PWD, USER, OLD_DIR and all that will be the same. This means if you schedule a command with a relative path it'll still work!

C++: incredibly useless stuff

Would this compile? What does it do?

int main() {
  http://nicolasb.com.ar
  return 0;
}

Answer in rot 13: Vg jbexf. uggc: vf n ynory, // vf n pbzzrag, gur erfg bs gur yvar vf vtaberq.

non-vacations

After some sick time, lots of work, prepearing my new blog (monosinfinitos.com.ar, go check it) and several other,personal stuff regular blog updates will resume tomorrow and continue at least for a week. That's about the buffer size I've left, after that I'll have to write something new or take a longer vacation... we'll see.

In the meantime, enjoy a pretty picture. [BROKENLINK]