Interview With the Author of "Mastering Cat"

Shlomi Fish writes "O'Reilly is publishing a new book titled 'Mastering cat,' about the UNIX 'cat' command. Here is an interview O'Reilly-Net conducted with the author about it. Read it to see if this book should be part of your bookshelf of technical books."

Comments

How about the followup?

[Fittysix]

?tac gniretsam

Re:How about the followup?

[Anonymous Coward]

I'd prefer the follow up "Mastering Pussy"

Re:How about the followup?

[prefec2]

The followup is "Echo Insights"

Re:How about the followup?

[exley]

Dude, this is Slashdot, and it's April Fools Day, not Opposite Day.

Re:How about the followup?

[lord_rob the only on]

rob@thinkpad:~$ pussy
bash: pussy: command not found

rob@thinkpad:~$ man pussy
No manual entry for pussy

Pussy doesn't even exist ...

Re:How about the followup?

[h4rm0ny]

Pussy doesn't even exist ...

That's strange. When I try:

h4rm0ny@mybox~$ grep -r pussy *

I get lots and lots of results.

Re:How about the followup?

[cayenne8]

Too bad there isn't a Unix command "Bater".....I'm sure that would be his next book.

:)

I think it would tend to be more of a self help book than a technical tome though...

Re:How about the followup?

[oldspewey]

No manual entry for pussy

I think I see the problem here - try starting her off with 3 or 4 vodka appletinis.

Re:How about the followup?

[Sir_Lewk]

'tac' is an actual *nix program, prints files out in reverse.

Re:How about the followup?

[upside]

Well I know where it's not:

-bash-3.2$ which pussy /usr/bin/which: no pussy in (/usr/kerberos/bin:/usr/local/bin:/bin:/usr/bin)

And then ofcourse there's

-bash-3.2$ man 8 pussy
No entry for pussy in section 8 of the manual

Re:How about the followup?

[Hognoxious]

I've never heard of it, but I wouldn't be surprised if it was true.

And I can imagine situations where it would be useful - for getting [part of] a log file in reverse chronological order, for one.

Re:How about the followup?

[palegray.net]

for getting [part of] a log file in reverse chronological order

Funny you should say that, it's exactly how I use the "tac" command.

Re:How about the followup?

[palegray.net]

pparadis@alpha:~$ vodka
bash: vodka: command not found
pparadis@alpha:~$ appletini
bash: appletini: command not found
pparadis@alpha:~$ tequila
bash: tequila: command not found
pparadis@alpha:~$ liquor
bash: liquor: command not found
pparadis@alpha:~$ beer
The program 'beer' is currently not installed.
You can install it by typing:
sudo apt-get install gerstensaft
bash: beer: command not found

Wow, I'm off to install beer on my laptop now.

Re:How about the followup?

[jonbryce]

pussy does exist, however there is no documentation for it, so you have to figure it out for yourself.

The other thing is, it isn't in $PATH, and slocate doesn't index it, so finding it is an exercise in itself.

Re:How about the followup?

[Bromskloss]

'tac' is an actual *nix program, prints files out in reverse.

And look, wow! There is even the reverse of tac, called cat, which takes the output of tac and prints it backwards. I wonder how many levels this continues. Maybe I should write a script to find out.

Then there is this command sl. Run it by accident when you are really stressed and it makes your head explode.

Re:How about the followup?

[jefu]

Of course, if cat didn't exist, you could always define an alias to "tac | tac".

Re:How about the followup?

[mikiN]

Pussy doesn't even exist ...

Hmm, there is a G-spot, but it's well hidden behind a cover.

$ dpkg -L gspot
...
/usr/lib/gnome-panel/gspot
...

Isn't IT great?

Re:How about the followup?

[Hordeking]

I'd prefer the follow up "Mastering Pussy"

My girlfriend loves it when I master her cat.

Re:How about the followup?

[ascari]

Or you could try some of the techniques from "mastering finger".

Re:How about the followup?

[gyrogeerloose]

Last login: Tue Mar 31 19 20:59:59 on console Macintosh:~ gyro$ man tac
No manual entry for tac
Macintosh:~ gyro$

Re:How about the followup?

[scotch]

How is that funny?

Re:How about the followup?

[Sir_Lewk]

http://linux.die.net/man/1/tac

It's pretty standard.

Re:How about the followup?

[palegray.net]

It hangs in the air the way bricks don't?

Re:How about the followup?

[DeBaas]

rob@thinkpad:~$ man pussy
No manual entry for pussy

have you tried entering automatically?

Re:How about the followup?

[andrikos]

You are in the wrong place, try first:
cd /pub

Re:How about the followup?

[k1773re7f]

"It is best to keep your mouth shut and appear a fool, than to open it and remove all doubt" -Mark Twain Dude, I think Sam was quoting Benjamin Franklin when he said that.

Re:How about the followup?

[Hognoxious]

There's two kinds of funny - funny as in beer, and funny as in speech.

Re:How about the followup?

[gyrogeerloose]

Must be a Linux app rather than BSD, I guess. Or maybe Apple just decided it didn't need to be included.

I tried mastering cat.

[SuperBry]

But I kept on getting scratched...

Re:I tried mastering cat.

[verbalcontract]

But I kept on getting scratched...

Next time try piping to /dev/null.

Re:I tried mastering cat.

[ControversialMatt]

There's your problem. It's not your cat, you're his person.

Re:I tried mastering cat.

[An ominous Cow art]

Woulds have been funnier if the author were "Claude Bawls", per the joke.

hmmm

[Em Emalb]

man cat

http://www.youtube.com/watch?v=Ex42OGGarrE

Usage: Not used. EVER. Run. Fast and far. QUICKLY.

I am not reading any more Slashdot until

[GlobalColding]

April 1st is over. Even under normal circumstances it is hard to judge seriousness of typical Slashdot posts, but today, I simply refuse to participate in filtering out April Fools detritus from the usual. I am going to get on my Amiga 2000 and play Giana Sisters. That is all.

Re:I am not reading any more Slashdot until

[Em Emalb]

Dear Sir or Madame, (if you are a madame, please respond with little black book, kthxbai)

Your frustration with the article posting selection with regards to the date of April 1st, 2009 has been noted.

Please understand that the most amusing thing to the majority of us is people who come to a site VOLUNTARILY on today's date knowing full well that the site will be filled with goofy articles and comments, some amusing, most not. However, your apparent frustration has been duly noted and will be filed with the appropriate authorities. Please be patient, as it can take up to several leap years for your complaint to be handled.

Have a pleasant day, and for God's sake, upgrade to a current gaming console, this isn't 1986.

Yours,

Cletedius P Moran
HMFIC
Slashdot Complaints Department
1st Marine Forces Expeditionary Unit
Baghdad, Iraq
888-867-5309

Re:Frist Psot?

[snowraver1]

There is, but it only works if you are logged in as AC and if you post either a goatse pic, a long post about Obama's shit, or an instruction manual for someone of african decent.

Damn.

[castorvx]

I was hoping for a manual to help me read the icanhascheezburger comments.

Re:Damn.

[momerath2003]

That would be "lolcat," not cat. And here is a page to help you.

Re:Damn.

[RobBebop]

Mod parent Insightful. His link explains how to Master Lolcat.

Re:Damn.

[Henry Pate]

Not to be confused with LOLCODE. Here's an Hello-World example taken from their site.

HAI
CAN HAS STDIO?
VISIBLE "HAI WORLD!"
KTHXBYE

Re:Damn.

[momerath2003]

Honestly, I never would have expected a +4 informative for linking to a page full of lolspeak. /shrug

Re:Damn.

[SwabTheDeck]

That would be "lolcat," not cat. And here [lolcatbible.com] is a page to help you.

Feh! Everyone knows that "lolcat" is just a symlink to "cat --lol".

Master

[Hogwash McFly]

You can't master any cat, only dogs. As the saying goes - dogs have masters, cats have staff.

Re:Master

[dargaud]

$ cat --help | wc -l
23
$ dog --help | wc -l
43

It seems like there are many more ways to manage a dog than a cat... No surprise here.

How hard is it to get CAT to work with HURD?

[TinBromide]

I've been trying to get my cat to play nice with gnu Hurd for a while. It seems like it starts to work, but then starts to ignore all IO and proceeds to SLEEP(3600). I am eagerly awaiting someone who can get a cat Hurd to work.

Re:How hard is it to get CAT to work with HURD?

[mrogers]

The trick to controlling a cat Hurd is pipes... lots of pipes.

Re:How hard is it to get CAT to work with HURD?

[Binestar]

Bravo!

Re:How hard is it to get CAT to work with HURD?

[kybur]

Nonono, pipes won't work at all. What you need are tubes... A series of them.

O HAI

[Oxy the moron]

I CAN HAZ DIS BOOK NOW PLZ??

Re:O HAI

[Bob The Cowboy]

I CAN HAZ DIS BOOK NOW PLZ??
--

Proudly supporting the Libertarian Party.

I knew it... lolcats is a grassroots movement started by the Libertarians to... uhh... get... cheezeburgers?

Re:O HAI

[TheSync]

knew it... lolcats is a grassroots movement started by the Libertarians to... uhh... get... cheezeburgers?

There is no such thing as HAZing a free CHEEZEBURGER.

Re:O HAI

[SwabTheDeck]

I knew it... lolcats is a grassroots movement started by the Libertarians to... uhh... get... cheezeburgers?

lolz, dis iz teh astroturfingz.

finally

[Lord Ender]

An april 1 tech story that actually made me laugh a little. Nice.

I'm going to print that cover so I can put it over an old book on my bookshelf.

Re:finally

[Hierarch]

Good idea. I was beginning to think I was the only one here who'd actually buy the book if it actually existed, just to have it on the shelf.

I just /usr/bin/cat my coffee everywhere.

[Mr. Flibble]

I guess I forgot what day it was, but the title article made me spew my coffee in laughter.

As an aside, remember kids, don't do this:

cat foo | grep bar

It is bad Unix! (If you don't know why, read the non-existent book on cat...) ;)

Re:I just /usr/bin/cat my coffee everywhere.

[steveha]

As an aside, remember kids, don't do this:

cat foo | grep bar

It is bad Unix!

Eh, it's not that big a deal.

Yes, you can simply say "grep bar foo" and it will have the same effect with less typing. But it's really not that big a deal, and there are times when I would do this. Usually it is because I'm doing something like this:

shell_script foo | grep bar

And I'm not getting the results I expect; then I might swap out the shell script part for cat, to help me debug. It's easier to type

cat !*

or even

^shell_script^cat

than to retype the whole command.

As long as you know what you are doing, build the command line any way you like. The computer exists to serve you, not the other way around...

Now someone will mod me (-1, No Sense of Humor) or (-1, Beating the Joke Into the Ground). But I regret nothing! Nothing, I tell you.

steveha

Re:I just /usr/bin/cat my coffee everywhere.

[TheRaven64]

The correct general way of doing it (which works for all values of grep) is:

$ grep bar < foo

You don't need to do this with grep, since it can take a file as input, but in the general case, any time you are using cat with a single file and a pipe you should be using <.

It doesn't make much difference when you are running a single command, but it makes a huge difference when you are running a loop or something like a find command. The extra cat doubles the number of fork() and read() system calls, adds a load of unnecessary write()s and adds a lot of copying that is otherwise unneeded.

Re:I just /usr/bin/cat my coffee everywhere.

[arth1]

There are situations where you can't use a redirect, but have to rely on cat and pipes.
Like for instance, file copying a file to a system that doesn't have an sftp-server:

cat filename | ssh hostname "cat - >filename"

Re:I just /usr/bin/cat my coffee everywhere.

[TheRaven64]

In this example, you only need one cat, not two:

ssh hostname "cat - >filename" < filename

Re:I just /usr/bin/cat my coffee everywhere.

[bar-agent]

The computer exists to serve you, not the other way around...

No! Don't you see? It's a cookbook!

Re:I just /usr/bin/cat my coffee everywhere.

[arth1]

True, but it's trivial to come up with examples where it's needed:

rsh host1 "cat filename" | rsh host2 "cat - >filename"

In short, cat can be quite useful in its simplicity.

Even in shell scripts, I too often see constructs like:

echo -n "Starting job at "
date
echo "----"
echo "Eenie meenie"
echo " minie moe"
echo "Catch a tiger"
echo " by the toe"
echo "----" ... which could easily be replaced by a cat:

cat EOT ;
Starting job at $(date)
----
Eenie meenie
  minie moe
Catch a tiger
  by the toe
----
EOT

It's time someone speaks up for underused commands like cat, at, dc, tee, seq and others that can be quite useful in a standard sysadmin arsenal. And cut down on the overuse of others, like echo, and, dare I say it, sudo.

Re:I just /usr/bin/cat my coffee everywhere.

[arth1]

Argh. The Slashdot reformatter strikes again.
Insert two less-than signs before the first EOT in the above... :-)

In the news today, a group of IT professionals ...

[Phizzle]

were found dead. Apparently they were playing a drinking game, and doing a shot for every lolcats reference on Slashdot.

Giana Sisters

[Tetsujin]

I am going to get on my Amiga 2000 and play Giana Sisters. That is all.

Giana Sisters... nice...

You know, though, I've listened to a lot of SID music and recently decided to check out some Amiga Music for the first time... I found the Amiga version of the Giana Sisters tune surprisingly dull compared to the C64 version. What is up with that?

Neuter to decrease aggression

[wonmon]

rm -r testes

Re:Neuter to decrease aggression

[kg9ov]

The cat probably won't be as open to that as you may think... I would suggest using the -f option as well, just to be sure.

Re:Neuter to decrease aggression

[upside]

How do you remove testes recursively? Are cat testes like Russian dolls? If so, is this somehow related to them having nine lives? Perhaps it makes sense. To kill a cat with any certainty you'd have to do something like

kill -9 $(ps axe | cut -d" " -f1 | tail -1 | head | cat)

which - as we know - is an arcane Unixish incantation to kill the cat by putting it in a bag and cutting somewhere between the tail and head with an axe nine times.

Or maybe you meant rm -f

P.S. I take no responsibility if you're stupid enough to run that command. Anything or nothing could happen.

Re:Neuter to decrease aggression

[upside]

And by "you" I mean the reader, not the parent poster. ;)

Re:Neuter to decrease aggression

[Zashi]

Parent's command only works after you touch testes

Re:Neuter to decrease aggression

[wonmon]

Honestly, I used rm -r because I was thinking that ball1 and ball2 (and sometimes ball3) would be subdirectories, each containing millions of incomplete cat executables.

Re:Neuter to decrease aggression

[Anonymous Coward]

-f I can see, but -r?! What kind of cat to you have that you need to recurisvely remove testes? o.0

Re:Neuter to decrease aggression

[jbeaupre]

I sincerely hope you don't have user privileges with cat's testes.

Re:Neuter to decrease aggression

[Tavor]

Also recommended: rm -rf front_claws

Re:Neuter to decrease aggression

[megaditto]

Inside the testes are smaller cats with smaller testes... In fact, it's the ever-shrinking copies of cats with testes all the way down.

Re:Neuter to decrease aggression

[Znupi]

-f I can see, but -r?! What kind of cat to you have that you need to recurisvely remove testes? o.0

Well, they have two of them, don't they? And you must make sure you remove both at the same time!

Re:Neuter to decrease aggression

[Tubal-Cain]

You'd be surprised how well they wield the back pair.

Re:Neuter to decrease aggression

[Hurricane78]

So it's CATS all the way down! I KNEW it!

Re:Neuter to decrease aggression

[Hurricane78]

Yeah. Let's try that with your nails too. Just rip them off. And your balls too.
Nice isn't it? Your long and enduring pain is so worth my little convenience of being a total pussy about cat scratches and the toootal stress of letting your cat out to find love.

Re:Neuter to decrease aggression

[MR.Mic]

if they aren't nested, you can simply use a wildcard.

Re:Neuter to decrease aggression

[laejoh]

How are you gentlemen!!

All your base are belong to us.

You are on the way to destruction.

Re:Frist Psot?

[Tim C]

No it isn't, and no, there really shouldn't...

Re:Frist Psot?

[CannonballHead]

What is this "African Decent" you speak of? :)

Still Waiting

[Kushieda Minorin]

I'm still waiting for "Mastering true" and "Mastering false". The delay is understandable, considering nobody is able to harness the true power of these two commands.

Re:Still Waiting

[Wildcat J]

I'm still waiting for "Mastering true" and "Mastering false".

It's funny that you should mention that. I don't remember how I stumbled upon it, but here you go: http://www.miketaylor.org.uk/tech/oreilly/truenut.html

Re:Still Waiting

[TwistedSymmetry]

They're working on a "Mastering yes" book, but I hear they're having trouble finishing it.

I use...

[Skiron]

...Schroeder's cat. If it works, you don't know it, but if it doesn't you have to try again until you get it to work (if you can tell that it worked anyway). Then the pipe comes out to stop my mind frying.

Re:I use...

[Tetsujin]

...Schroeder's cat. If it works, you don't know it, but if it doesn't you have to try again until you get it to work (if you can tell that it worked anyway). Then the pipe comes out to stop my mind frying.

That's "Schrodinger's cat". Your license to make quantum mechanics jokes is hereby revoked. To make sure you don't try to take your license back, we're going to keep you updated on its current velocity.

Re:I use...

[eXonyte]

Funny, I never realized that Schroeder had a cat...

Re:I use...

[Mattintosh]

Watch out, he might start using a Heisenberg Compensator. Then you're screwed.

Of course, if he uses one, he'll have to build it first, and if he can build one, he'll have earned the card back anyway.

Re:I use...

[saforrest]

That's "Schrodinger's cat". Your license to make quantum mechanics jokes is hereby revoked.

That's Schrödinger's cat. Your licence to use Latin characters outside the 7-bit ASCII range is hereby revoked.

Re:I use...

[kybur]

I had a QM professor named Schroeder in grad school. Maybe the parent did too. That joke came up more than once.

Re:I use...

[Tetsujin]

That's "Schrodinger's cat". Your license to make quantum mechanics jokes is hereby revoked.

That's Schrödinger's cat. Your licence to use Latin characters outside the 7-bit ASCII range is hereby revoked.

Well, I don't have a license to use Latin characters outside the 7-bit ASCII range - which accounts for why I didn't. :D

But, still, touche. (D'oh! I did it again!)

Re:I use...

[Sulix]

It's better to say touche. Touché is too cliche.

Re:I use...

[MichaelSmith]

I don't recall observing one.

Re:I use...

[Seriousity]

Don't be such a douché.

It took 2 Programmers!

[jellomizer]

AUTHOR
              Written by Torbjorn Granlund and Richard M. Stallman.

My guess is Torbjorn Granlund coded it and RMS takes the credit

Well done

[bulletman]

Funny writing. It was obviously a joke, but the concept was so funny that knowing this going in didn't change anything.

Re:This isn't even a good joke

[KarateBob]

I agree

Rings too true

[mewsenews]

It's obviously an April Fool's prank, but I wouldn't be surprised if there was an entire book dedicated to the more obscure uses of cat and differences between GNU cat and others.

My logic for this is reading about netcat, being completely bewildered, and being even more completely bewildered when the description of sample command lines read that it "works just like cat!"

Re:Rings too true

[anothy]

give the gnu folks some time to add more options. you really will need a separate manual eventually. they'll incorporate most of the uses in the interview as --prepend-input or --bookend-input. right before they make the man page just point to the info page, and start adding networking support like the stupid gnu awk has.

my cat, from Plan 9, has 0 options. cat concatenates files. end of story.

Re:Rings too true

[mewsenews]

haha, i wouldn't doubt it.

I'm more intersted in tail than cat.

[Maxo-Texas]

If they released a book on how to master tail (heck, even find tail), it would change slashdot forever.

Re:I'm more intersted in tail than cat.

[drooling-dog]

That would be useful. And if there was one on mastering head, I'd buy it for the GF...

Re:I'm more intersted in tail than cat.

[wonmon]

:(

I have trouble even getting "touch" to work

Re:I'm more intersted in tail than cat.

[jlowe]

Well... mastering "cat" does fall along the same lines.

Re:I'm more intersted in tail than cat.

[A Commentor]

Did you even look:

$ which tail

/usr/bin/tail

And for info...

$ man tail

TAIL(1) BSD General Commands Manual TAIL(1)

NAME

tail -- display the last part of a file

Re:I'm more intersted in tail than cat.

[Maxo-Texas]

Lol.

I'd "whoosh" you... but I suspect someone would "whoosh" me then for some reason I don't get.

Re:I'm more intersted in tail than cat.

[Just Some Guy]

Alternatively, you could master head. I hear there's demand for it in certain log processing circles.

Re:I'm more intersted in tail than cat.

[fwice]

>---joke--->

   O
  \|/    <--- you
  / \

WHOOSH

Re:I'm more intersted in tail than cat.

[SpottedKuh]

$ man tail

I think he may have been looking for the other kind.

Re:I'm more intersted in tail than cat.

[A Commentor]

No shit Sherlock... You do know the concept of taking the joke a little farther?

DOUBLE WHOOOOSH

Re:I'm more intersted in tail than cat.

[ArsonSmith]

# info tail?

Re:I'm more intersted in tail than cat.

[RussianPhysicist]

Coming soon to your nearest bookstore:

• "The art of touch"
• "kill HOWTO by Hans Reiser"
• "sleep in a nutshell"
• "First date for dummies"
• "bash: the martial arts basics"

C'mon, it's been done already

[k2dbk]

How will this ever outsell the wildly popular "Cat for Dummies"?

Re:Stop it with the bitching already!

[s_mencer]

All the people bitching about the April 1st content should:

cat > senseOfHumor [enter key]
I didn't use '>>' because I wasn't worried about overwriting an existing file. [enter key]

Here goes:

[IceCreamGuy]

~# date
Wed Apr 1 13:31:50 EDT 2009
~# links2 -dump http://slashdot.org/ >> humortest.txt
~# cat humortest.txt | grep $somethingfunny
~#

Re:Here goes:

[morgan_greywolf]

You should really have RTFA. That's a UUOC. You just completely wasted a process call and unnecessarily wrote to a file:

links2 -dump http://slashdot.org/ | grep $somethingfunny

Of course, if we look at your use of an appending redirection (>>) (assuming humortest.txt already exists and has useful data), then you still unnecessarily wrote to a file:

links2 -dump http://slashdot.org/ | cat humortest.txt - | grep $somethingfunny

Re:Here goes:

[IceCreamGuy]

I know, I wrote that all out, and then I was like "wait, shit, I can just grep it right from the links2 output." So I wrote it on one line... but then I realized I wasn't using cat anymore and it ruined the joke. Please don't judge me!

P.S. thanks for introducing me to the phrase "UUOC," now I have something funny to read!

Re:Here goes:

[mattack2]

Specifically (to save google a few processes.. heh)..

http://www.websters-dictionary-online.org/definition/UUOC

Re:Here goes:

[curunir]

You must not have gotten to the chapter entitled "Advanced Cat" (page 2). Cat can also be used as a target for piped output.

Try: ~# wget -o /dev/null -O - http://www.slashdot.org/ | cat | cat | cat | grep $somethingfunny
~#

Voila! No temp file needed. And all due to the power of cat (hint: the third one is the most important.)

Talk to the guys at

[wiredog]

EDS.

Don't joke about that.

[GoNINzo]

You can joke about mastering cat. hah hah. funny. sure.

But don't mess with echo, though. When everything else breaks on your unix OS, and you only have builtins alone, you just need echo and some pipes to get it back on it's feet.

This really isn't that unrealistic

[FreakerSFX]

Many discussions between real nerds about seemingly trivial OS topics have gone on for far more than book-length of obscure, historical and political commentary. I sort of find it humbling how much history there is for a lot of the components of UNIX.

I am inclined to stay out of these conversations. I never advertise my point of view because I can't be bothered to try and convert the evangelists to my point of view. I won't convince them, they won't convince me; we'd just end up annoying co-workers and further marginalizing ourselves socially at work.

Re:god

[bigstrat2003]

Protip: IGNORE IT.

Seriously, if you hate all these stories so much, leave /. for the day. It won't kill you. You know they're going to be here all day, so come back tomorrow. You'll be happier because you won't be reading the stories, and we'll be happier because you won't be bitching about our fun.

dog link is broken

[Olaf Underbridge]

<http://jl.photodex.com/dog/>, the link given for the
dog program, is broken, and the first Google hit
seeking a replacement is unresponsive (probably /.ted).

However, <http://manpagehelp.net/manpage/linux/man1/dog.html>
gives a good overview.

Debian/Ubuntu: sudo apt-get install dog
Gentoo:        sudo emerge sys-apps/dog

Great Book!

[LaminatorX]

I much prefer Mastering cat to Teach Yourself cat in 24 Hours.

Upcoming second edition in 2012

[Tetsujin]

The second edition of "Mastering Cat" will include in-depth coverage of the use of "cat" in the new generation of object-oriented Unix shells. Key topics will include:

• "cat" type safety
• Using "cat" in traditional mode vs. object-oriented
• "cat" pitfalls: attempting to run "cat" on non-serializable live objects, "cat" on lists vs. "cat" on text files, using "cat" to capture user input (and dealing with the untyped data stream that results...)

You think I'm joking? Watch me. Hopefully what I come up with won't be quite the nightmare I'm trying to describe above. :D

Re:Upcoming second edition in 2012

[jefu]

You forgot : "cat" as a monad injection tool (which is the oft-belittled UUOC).

Re:Upcoming second edition in 2012

[iris-n]

I sincerely hope so. Countless times I've seen my students forgeting all the good manners of using object-oriented cat, like in this shameless UUOC:

n00b@nix:~/bin$cat >> cat.cpp
#include <iostream>
#include <string>
main(){
std::string a;
while(42){std::cin>>a;std::cout<<a<<'\n';}}
^C
n00b@nix:~/bin$cat cat.cpp | g++ -o cat
n00b@nix:~/bin$cat >> dog.cpp

But...

[cstdenis]

it's not even Caturday yet.

Must be rubbish, no mention of tac...

[weeble]

Any book about cat must include tac. I cannot believe the interview didn't mention it once.

Very disappointed, tac is at least as complicated as cat.

Donkey Ears

[lazy_playboy]

It's gone midday. Donkey ears for you.

Using mouse to master cat

[AliasMarlowe]

'nuff said, check today's date.

Re:Using mouse to master cat

[rhyder128k]

I know for a fact that Universal optioned the rights to this book. Unfortunately, Paramount had entered post-production for Echo: The Movie! so I don't think that Universal are going to pursue it. As long as it stays true to the dark themes of the original, I don't care what file command movie gets made. If it's a origins story, we'll probably get to see Edlin. Kevin Spacey, anyone?

Re:god

[MyLongNickName]

leave /. for the day

But.... I'm working on 12 points in my consecutive days on Slashdot achievement.

Re:Frist Psot?

[cayenne8]

"What is this "African Decent" you speak of? :)"

Well, it is like regular Descent, except rather than flying through caves, you are flying through a dry, arid desert area. And rather than lasers and smart bombs, you get a spear. If lucky, you get a power up weapon of a coke bottle that comes to you from the gods in the sky.

In case you were wondering what the book's like...

[Anonymous Coward]

here's a what a simple cat implementation looks like (The book leeaves additional features as an exercise to the reader):

HAI
CAN HAS STDIO?
I HAZ A VAR
MAEK ARGV[1] A TROOF, O RLY?
  YA RLY, VAR R ARGV[1]
  NO WAI, VAR R "STDIN"
OIC
PLZ OPEN FILE VAR?
  AWSUM THX
      IM IN YR FILE EATING UR LINES
    VISIBLE LINES
      IM OUTTA UR FILE
  KTHX
  O NOES
      INVISIBLE "ERROR!"
KTHXBYE

can't wait for the sequel..

[midnightclimax]

"mastering tac". uhhuhu.

Catting Cat

[Chlorine Trifluoride]

cat Mastering\ Cat.pdf > /dev/null

But seriously

[Sloppy]

For example, one case where I found that people truly underestimate the power of cat is in the prefixing a line example. You can do that with:
echo "This would be the first line" | cat - myfile.txt > myfile.txt.new mv -f myfile.txt.new myfile.txt
But people do not realize that and instead opted to use sed, awk, or even perl (!).

I've done that.

Re:But seriously

[Sloppy]

Actually, I wasn't even looking at the rest of the pipe where he creates a temp file. I just meant that I've use awk for doing nothing other than prepending/appending a line of text to a stream, e.g.
awk 'BEGIN { print "hello" } { print $0 }'
Kind of overkill. Oh, and by the way, perl is disgusting.

Re:This isn't even a good joke

[Smivs]

It's better than mine, which is truly lame, and plugging it here is the only way I'll get any hits!

awesomeness

[Satanboy]

This was a good one!

We now need a book on Mastering SUDO . . .

I'm holding out...

[MoreDruid]

I'm holding out for next year's title: tac

there must be more to that than cat spelled backwards

Re:Frist Psot?

[Colonel Korn]

Maybe? There really should be an achievement for this.

There should be an automatic ban for anyone who posts "First" or "First Post" or any variation thereof.

Re:Frist Psot?

[sanjosanjo]

I believe there should be.

I guess we're lucky

[DigitalReverend]

that there isn't a command or language called BATE. Of course most of the people here wouldn't need a manual for that.

The beginning of a new serie

[gmuslera]

This book will become part of a new O'Reilly serie. The other books will be

touch cookbook
Running grep
Practical uniq Management
Advanced fsck for system administrators
|: The missing manual

Re:The beginning of a new serie

[Rick Genter]

You left off my favorite:

Advanced yes

Re:Frist Psot?

[CannonballHead]

Oh, cool, so it's like an expansion back?

(incidentally, I remember playing Descent...)

Re:god

[Patch86]

Except that all the other flipping news websites and blogs are at it too...

Bloody everything...

Wrong cover

[dlsmith]

O'Reilly would never put a picture of a cat on a book about "cat". It's way too obvious. (Well, nevermind.)

Re:Wrong cover

[dlsmith]

Oops. Broken link.

http://oreilly.com/catalog/9780596006099/

Re:Wrong cover

[quarterbuck]

Actually I think the picture on that page is of a Lynx. http://en.wikipedia.org/wiki/Lynx

Re:Frist Psot?

[spiffmastercow]

you're just trying to get a contradiction achievement.

Re:Frist Psot?

[Scott Francis[Mecham]

Does the bottle need to be returned at the end of the game, though? Or is that a bonus mission?

Re:Frist Psot?

[Jurily]

How about a "Score 5 First Post" achievement?

man man

[hansamurai]

The other day I tried to bring up the man page of man, and it didn't have one. I was sad.

Re:man man

[makomk]

It should do, you just need to make sure you have the manpages installed.

Re:Geeks shouldn't do marketing

[Tavor]

And Slashdot users would be terminally confused.

OMG! KITTENS

[mdsolar]

This purrfect for today.

Cat is useful. Really.

[Anonymous Coward]

These jokes are becoming lame, but cat is definitely one useful tool.

Well, I'm sure they can come up with an OReilly cookbook for cat. Cat is handy in a lot of situations. Consider these:

Concatenating the output of two PS files. Then you can merge two documents together into a single PDF.
Concatenating your .signature to an email message, useful in scripts.
Concatenating your self-extracting executable to its' data.
Using cat to pipe data into multiple filters all at once, without needing temporary disk space.

I wouldn't be surprised if there was such a book at all.

Re:hm

[corvair2k1]

So submit a better one... I'm sure that these are driven by user submissions just like always.

what are you talking about?

[nobodylocalhost]

Everyday's Caturday.

A real cat tip

[TechwoIf]

To do a simple config change that requires adding a file but don't want to go though the entire process of creating a patch file. One can do this within the shell script.

cat << EOF > /etc/udev/rules.d/91-spacenavigator.rules
KERNEL=="event[0-9]*", SYSFS{idVendor}=="046d", SYSFS{idProduct}=="c603", SYMLINK+="input/spacemouse", GROUP="plugdev", MODE="664"
KERNEL=="event[0-9]*", SYSFS{idVendor}=="046d", SYSFS{idProduct}=="c623", SYMLINK+="input/spacetraveler", GROUP="plugdev", MODE="664"
KERNEL=="event[0-9]*", SYSFS{idVendor}=="046d", SYSFS{idProduct}=="c626", SYMLINK+="input/spacenavigator", GROUP="plugdev", MODE="664"
EOF

The "ecode" is adding extra lines in there.

Re:A real cat tip

[goarilla]

lol i usually do it slightly different

cat > /etc/resolv.conf << eof
domain="domain"
nameserver=ns1...
nameserver=ns2..
eof

i had to write a script to do this cause for some
reason fedora keeps breaking itself after updates
and dhcp and networkmanager suddenly became unuseable

Here it is!

[jbeaupre]

http://www.amazon.com/Master-Cat-David-Garnett/dp/0333178378/ref=sr_1_5?ie=UTF8&s=books&qid=1238611553&sr=8-5

Re:Frist Psot?

[Hognoxious]

a power up weapon of a coke bottle that comes to you from the gods in the sky.

I thought I was the only person who's ever seen that film. I suspect the intersection between those who get it and those with modpoints will be the empty set.

Misreading Title (was:I tried mastering cat)

[Anonymous Coward]

But I kept on getting scratched...

That's probably because you misread the title as masturbating when it should have been mastering. (Sorry, it had to be said.)

Good luck

[roystgnr]

I've been told that Hurding cats is like trying to control large numbers of some sort of small obstinate animal.

It's 2009!

[recharged95]

Come on, it's 2009, shouldn't it be 'Mastering lolcat'?

Re:Frist Psot?

[fprintf]

Been there, done that. A few years ago I got first post and a +5 (w/o karma bonus) interesting. I don't see it listed on my achievements list, but I was pretty proud of it at the time. I think a few of the following comments even said that it was the first time they had seen such a beast, and this of course was when "first post" was an interesting challenge and something noteworthy to attain. Nowadays, meh!

No no

[roystgnr]

The Libertarians want you to realize that people can efficiently and honorably Haz their own Cheezeburgers. The allegories are subtle: you can rely on the Invisible Hand of the market to bring your Invisible Sandwich, and you can do it all without empowering the dangerous surveillance state metaphorically represented by Ceiling Cat Watching You.

Re:Frist Psot?

[blueZ3]

No he's not!

Re:Frist Psot?

[treeves]

No, he's not. There's no contradiction achievement.

Already Reading

[DevCybiko]

I couldn't find it on either Amazon (for my Kindle) or on O'Reilly. But I got a lot out of the article. I was surprised that he didn't include versions for Linux, but maybe that's in another edition of the book.

Re:Frist Psot?

[Cyberax]

Nope. I've seen it too.

Re:Frist Psot?

[alexhs]

I suspect the intersection between those who get it and those with modpoints will be the empty set.

Nope, I have modpoints. But no more for this story, GP got +5 funny anyway.

You forgot to give refs :
http://en.wikipedia.org/wiki/The_Gods_Must_Be_Crazy
http://www.imdb.com/title/tt0080801/

Re:Frist Psot?

[Stauken]

So what does that make 'Irish Terminal Velocity'?

i prefer polecat

[pak9rabid]

sylar:~$ polecat how_to_get_rid_of_skunks.txt
bash: polecat: i hate you

Iknowallaboutcat.I'vebeenusingcatforquitesometime.

[b4dc0d3r]

Thisbookisveryhelpfulbutmissingaveryimportantchapterinmyopinion.Iusecatoneverythingnow,it'slikemyownmini-vi,ormini-emacsforthoseofyouwholikeemacs.Ihaven'treadeverychapteryet-Ireadalittleslowly.ButonedayIwillbeacompletemasterofcat.Catmaster,that'swhattheywillcallme.

So...

[PPH]

...what's the pix on the cover? A dog?

In all seriousness...

[Ross Finlayson]

I wish people would 'master' "cat" enough to know when *not* to use it. For example, I'm tired of seeing
cat filename | application
instead of (shorter, and more efficient):
application < filename

let me know whey they publish "Herding Cats."

[swschrad]

for in such there is a lot of money to be made.

all that happens when I "cat furry" is I get bit on my machine.

Re:hm

[el americano]

On second thought, please don't. We've had enough for one year.

predictable

[ascari]

Did you expect any less from the folks that publish make magazine? (Two UNIX command references in one sentence! I win! We can all go home now.)

obscurix

[sbeckstead]

I tried
schroedinger>mkdir /box
then
schroedinger>mv cat /box
Then when I went to look in /box
schroedinger>ls /box I found two files...
cat cat.dead
it's not in the manual...

Next up...

[tehBoris]

Mastering yes.

next book is a guide to fishing lures

[vaporland]

master baiting

Re:god

[sgant]

The only thing annoying about this day is all the idiots with no sense of humor saying "make it stop" or "isn't this day over yet".

Seriously, remove the sticks that are up your asses and lighten the hell up.

Re:Frist Psot?

[Hognoxious]

I didn't fortget, I just couldn't be bothered.

Re:Frist Psot?

[spiffmastercow]

There is.. (check my achievements, its actually "Contradictor"), but this isn't how you get it.

Re:Frist Psot?

[treeves]

I was just contradicting him. You know, a joke.

How about "Getting a Grep On Your Log..."

[FireStorm69]

Getting a Grep On Your Log: 101 Ways to Maximize Your Log Usage

You will need to have a firm grasp on tail and head as well as know the difference between less and more in order to truly master your log.

Caution should be used when using cat on your log as it could damage your log permanately (sharp claws and teeth, OUCH!)

--
In a mad world, only the mad are sane!

Re:Frist Psot?

[Hognoxious]

My faith in humanity[1] is restored [2]. [1] at least the subset that lives in underground sub-dwellings owned by the maternal parentical unit. [2] well actually it isn't. Life is shit.